I think this is a great idea! Having been a canon user, i extensively toyed with CHDK and i think i have some ideas. Correct me if they have already been implemented and i don't know how to use my camera...
So, things i miss:
1) An intervalometer. I don't think this could be too hard... Just a drop down menu to specify number of shots, separation between shots and time to first shot.
2) Aperture bracketing? I find this quite useful depending on the lens you are using...
3) Scripting. Ok, this is a long shot. I read here (i think) that pentax cameras use a special OS, but.... there's nothing wrong with wishing, right?
Anyways, i'm sure i left something under the table, so if i remember, i'll post it.
PS: More than 3 shots when bracketing!!! Why only three???
And how about specifying shutter speed for longer shots??
That's it!!