I'm glad to hear that you fired up the old engines again!
Back in the day, I wrote a simple tool in PHP to do all the dirty work such as:
- small internal "bloglike thing"
- file indexing (users add either one at a time through a HTML-form or upload an m3u-playlist to add lots of files at once)
- file searching (of course even if people are offline)
- file requesting
- invitation (one member invites, another one has to approve)
- keyfile spreading (generation of a keyfile from all gathered keys)
I also thought of a way to encrypt the whole database but never really got around to try it. If anyone of you is interested in it, I could try to get it dusted and maybe put it on here as well.
Sounds cool. If you can find it post it, I would like to check it out.