Virtual compressed & encrypted drive - is it a viable idea?

I have some thoughts that I'd like to share with Wilders folks, and would appreciate any advice or ideas. We are a small software company, and while developing our main product, as a side effect we got a technology that allows to create compressed and encrypted virtual drives. Basically it's a driver that mounts a file (compressed and encrypted container).

The main emphasis we put into getting very high virtual drive speed (both read and write). It's comparable to the physical drive speed that the virtual resides on. Sometimes it's even higher (if the data is well-compressible).

This tool could be used if you have an external high speed drive, and there is some data on it that you need to use extensively, without copying to the main drive. Naturally, you would want to encrypt its contents, and compress the data to save space. Another advantage is having only a single file (the container) on your external media, rather than thousands of files of your data.

Also, this technology allows to create snapshots of the virtual drive - just like you do in virtual machines. I.e. you can instantly create a snapshot, modify the drive, then revert the changes. Or you can keep a chain of snapshots for versioning.

There are some similar programs like TrueCrypt (doesn't support compression), or WinMount (supports compression, paid, and slow). None of them supports snapshots.

I was wondering if there is a demand for such software. We could give it away for free, because it's a side project. Or maybe you can suggest some other use for it. Let me know what you think guys, thanks!

Isso