I might be able to set something up for you.

If you could answer the following questions, we can work something out:

• What are the quantities you will be ordering per month ?
• Are you going to fully dropship? No stock in your warehouse ?
• What is your expected price per tshirt ?

Feel free to answer them in a PM if you want to.

It has been a while since I last dipped my foot into a similar path ^{[I might not be that updated]} but I believe you can achieve your targets with the help of "Shopify ^{[just create your own store]}".

- You can use "Printful ^{[or other similar POD apps]}" with it.
- You can accept BTCitcoin and few other crypto-currencies.
- Lots of tutorials online.

most retailers wouldnt accept bitcoins, they are legit businesses so why would they accept crypto?

I was trying to find that when I was doing the print on demand business. But I didn't find anything. I suggest you to go for the fiat currency. And for dropshipping and custom store I will suggest you to use Printful as a t-shirt printing company. Their quality and service are best in the industry.

I have a source in India which can print the tshirts for you and accept bitcoin. Drop shipment also possible but the shipping cost will be high.

I think the picture is small enough, you can make it bigger so it's more readable and will caught the attention of whoever sees it.
The design is not that superb, I don't know maybe I would appreciate it more if its' printed in black T-SHIRT, sorry, I just love Black.

That's my honest review on the t-shirt. 

Don't focus on bitcoin theme t-shirt only since the market is not quite high for that matters just create a good design in relation to bitcoins so if the other user could see that then provably they will avail your product if they love what they see. As well create some good stuff and other things which can pass to the peoples taste since for sure people will not always wear a bitcoin t-shirt everyday so better to have an option so if people will seek for another design you can present the other one..

I'm somewhat disappointed that the other designs have dropped Satoshi's quote, but maybe it'll come back in a nicer design.
From the new batch the most I like t2.png. It's not perfect, but I like the idea and the comparison.

Ditto. The designs pretty much look like just a few images from the internet copy-pasted and clumped up together.

Also, I hate that they place huge lovebit logos. I know that it's for branding purposes, but again, the design as a whole is really lazy in my opinion. Just photos slapped around here and there.

I also thought of this, as much as I want and show it to the people on the road that I'm a bitcoin enthusiast and supporter I just can't. I might purchase one in the future but I'll wear it only at home.

@lovebit, does the design 2 can be customized by the customer and put his QR code in it? or is that even possible?

I get them mostly for free and hardly buy like most users have already indicated. In my collections of bitcoin t-shirt never I have owned any that speaks just about bitcoin as it always get accompanied by either those promoting their service like exchanges, meetups, conferences, wallet providers etc or those sponsoring a charity event like the one I just successfully completed.

Over here in Africa, one of the effective ways of promoting your brand is through distributing t-shirt with you logo displayed on them and since bitcoin is quite popular, most project use it's reputation to promote their brands, like I have t-shirts promoting exchanges with bitcoin logo on them.

I'm also fun of customizing my own t-shirt so guess that's why I hardly buy them too. About what I like most, I'll go for high quality since it means your design will last longer. Giving more attention to design than quality is a waste of money although if justice can be done to both then it's better that way.

You have to adjust the size of the design and the details, as most designs appear from the middle of the abdomen and focus on the bottom of the shirt, not the top.

 - size of the print area: It’s better to edit it to 12×16 inches.
 - File resolution: 150 DPI  to 200 DPI

I suggest you redesign it as the following design^[1] with an abbreviation of the words like (Don't believe it. I Don't have the time to try to convince)
Also, the yellow color seems distracting.

[1] https://www.pinterest.com/pin/479492691559166814/

Sorry to say, I don't like it. The Satoshi quote is cool, but the image with the thinking/unconvinced person and those paths/thoughts I don't like.
Maybe I'm old fashioned, but money or payments may go better. I mean, since we don't care to convince them, we don't pay attention to the direction of their thought, we just presenting what we have: "A Peer-to-Peer Electronic Cash System"(^TM)

Do you really create it yourself without stole other design?

https://i.ibb.co/NYwP7st/Screenshot-8.png
https://yandex.com/images/search?url=https%3A%2F%2Ftemp-ca.s3.amazonaws.com%2Fcdn-files%2Fris61539317sst1590676172.png&rpt=imagelike&source=collections&cbir_id=2472573%252FJmzDtHliDIVru0Z1WkfupA

If this design have copyright protected from the creator, you'll have problem/penalty in the future. You need to get a license or permission before you want to sell this t-shirts. I suggest you to learn about copyright here https://www.rivaliq.com/blog/guide-copyright-fair-use-laws-online-images/

I don't want to discourage you, but I've been on that road ^{[online store with the help of platforms that handled the shipping process]} a few years back and I wasn't pleased with the outcome...
^{- I've seen a lot of other users doing it as well and most of them, don't last that much.}

• 50% quality
• 50% design

I hugely doubt people will buy Bitcoin T-shirts and wear them in the streets. LeGaulois said correctly, just t-shirt with bitcoin logo won't be popular but on another hand, T-shirts with I ❤ NY and Supreme T-shirts were very popular and behind them, there is great marketing that requires a lot of money and believe me, it doesn't worth for bitcoin t-shirts.
I think it worths for you to check these articles: Why is Supreme so popular and this one - Some information about I love NY.

Also, bitcoin shirt, crypto fashion and related keywords have very low search volume in google (in USA and UK definitely) while competition is pretty high because of Amazon, Aliexpress and others.

You won't find any commercial success here, I remember user Condoras was seriously taking this job, to make crypto themed puzzles but as far as I know, it failed (check thread if interested).

Cryptocurrencies, generally speaking, I have some.
I don't buy it, I prefer to wait for the community managers to give it to me for free. After all, why pay for it when they advertise for free? Imagine all the people who drive by and see advertising while I rest in my garden. Much cheaper than what supermarkets spend on an advertising slot on the roadside. 

On a serious note, to make me buy it, it has to be a fucking good logo, not just the original. (I like neon colors for example). And secondly a good quality Tshirt, not the shit quality you find in supermarkets and whose colors are washed out after a few washing or that shrink.
And of course, at a reasonable price. Basically I know how to design and print it with Visatprint or any other for a decent price so I could DIY