I finished my first whack at a draft spec for Mint just now. I've gone about as far as I can go on my own and now need input from trusted friends to finish fleshing out the design. Then I can publish the spec and start work on the software.
I know the general concept is sound -- I've built 2 iterations of a testbed, and people agreed that they were Good. This, though, is a carefully thought-out-from-the-ground-up type thing. I sincerely hope it turns out well and turns out useful.