Another thing I'd love to see... I'd love to see a way to perhaps, cast a different rank of a spell on, perhaps a right click, or alt/ctrl/shift/whatever click. This was something I did a while back when trying out flexbar. I'd have the full rank setup for left clicking, and on a right click for say, shaman shocks, I'd cast rank 1 (or any rank you wish of course, why not?). I also had a shared left/right click button for max rank lightning bolt and max rank chain lightning.
Would any of this be possible? (the latter especially :>)
This is actually very much possible with BT3 and the new Template in TBC. This can be done with ie. another module. Iriel has done something like this to demonstrate the TBC Actionbars and it works just the way you wanted.