ok hard one Mist time

ok so I want to use Mist in the GE and blender kindly supplies mist, but I would like to be able to make the mist only exist inside certain objects wireframes in game and make it fade in and out of existence and move around all nice and randomly.

so three things:

1: mist placement control by object geometry

2: Mist fade in and out of existence when told to by game logic (could be nice)

3: mist motion and random shape generator.

is there any way to code this?

in 2.49b would be preffered (got a whole bunch of other scripts that don’t work in newer blender yet.)