Portable Ramdrive (is it possible?)

I may be dreaming and certainly don't have the expertise to create such a program, however ...

Would it be possible for a stand-alone application to create a virtual drive on the fly (like truecrypt, etc.) which instead of using space on a physical drive, used ram?

Issues I can forsee ...
* Would probably require administrative rights (like truecrypt).
* OS could chose to write some of the info to disk in a swapfile.