Where do you want your customers to host their original files - "You send me url's to files you want to download (via PM), I send you back url's with unlimited speed download. Simple Wink"

BTW.. Unlimited Speed. I'll assume you mean Unlimited Bandwidth.

Free hosting perhaps?

Huge flaw in your Offering. They will realize when sending the files to you, they can do it for free. Yes.. FREE. Like at one of the following sites.

http://www.mediafire.com/
http://www.filedropper.com/
http://www.sendspace.com/
http://www.zippyshare.com/
etc...

You can say I misunderstood and that you are going off "Security" or "No Ads"...

To which I will reply

No Ads = Stupid for a simple file you are only going to download a few time. However, some people MIGHT go for this
Security = There are thousands upon thousands of file hosting sites (a lot of free); with more money, and more security audits. What makes you more secure than them.

Good luck with your service, but the above are simple facts you should look into.

If you are worried about Download speed limiting, use a smaller lesser known File Host that is free. They don't use all their bandwidth and won't limit speed because they want to gain users.