Great project!
Will you ship worldwide - can we preorder it with certainty?
Thanks! Yeah I want to ship worldwide but I may have to charge extra for international shipping. I'll have to get shipping quotes and see exactly how much the difference will be.
Right now I'm not taking people's money yet, I just want to know how much of each part to order. But when I send out an invoice towards the end of June, it's very much certain your product will be shipped within the next few days. I'm not sending out the invoices until I have all the parts sitting in front of me, with multiple sample units built and tested with at least 1000 prints tested on a unit.
Ordering all the parts before taking any money is a huge risk on my part, but if I run into any sort of hiccup and need more time, I won't have your money hostage and I won't feel bad about delaying the ship date to make a better product. I've literally sold the majority of my bitcoins to finance this (at $117/BTC, damn it! haha), but I've been a member here for over a year and I've seen all the scams and I know how sensitive everyone is and stuff. I intend to make the process fully transparent, with verification photos of myself with all the parts and supplies posted here before I send out the invoice so you can really be confident sending me your money.
What about refills of the paper?

Great question, I'll be selling refill rolls for $1 each. Each roll will print over 100 paper wallets.