Edit : As FATEScape didn't generate a lot of interest, I'm happy to go with FATE or any of its derivatives. The original concept still stands, and the no longer relevant part of my original post is in spoilers in case it's useful at all.
So there's this game that potatocubed of these forums is working on. It's not strictly finished, so we'll need a GM of some experience with FATE or just GMing in general. It's definitely in a playable state, though, so don't let that put you off. You'd need to either have some D&D books or find a wiki with the flavour stuff, though. Planewalker is one example of a site that has a wiki etc. with info about Planescape.
The game can be found here. Check "Downloads" on the right side.
What I'd really like to do is planar exploration, preferably the Inner Planes (including the Para- and Quasi-) and the Astral/Ethereal. I'm happy to check out some of the Outer Planes instead, though, if people would find that more interesting. A balance of Sigil and planes would also be fine, as long as there is some planar exploration. The Planescape factions and stuff are fine if people want to look at those, and if we're doing that, I'll definitely get involved.
I'd really like to do this, so I edited the original post to expand to any FATE game in hopes of attracting interest. If there's some system somebody would really like to run besides FATE, I'm very flexible.
EDIT: Guess not. I'll unsubscribe from this now, PM me if you want me.