a) Internal gravity without gravitic generators
b) Instability on only 1 axis rather than 3 (and possibly correctable to passive stability)
I've always wanted to use this in a Role-playing game, but I've never been able to do the math to solve for the outer shape of the thing (which isn't spherical).
Now that I have mathematica, I may one day take another shot at it (but I'll have to go and restudy my vector calculus, as I haven't needed it in the 20 years since I left College).
In the meantime, if anyone else want to try and do the math, there is a write-up here in my journal.