I have actually had similar service running on my servers for a while now (took me about almost 3 months to design, code and test), though it makes legally no sense to make it available to the public, as you will need a solid ISP that will guarantee you that it won't abandon you as soon as they receive a letter from the Copyright Mafia. The service will eventually resemble a glorified cyber locker, since it makes no sense to delete the most popular files. Secondly, you aren't really protecting your customers unless you can provide payments through bitcoin, but even that wouldn't be safe enough.