I'm wondering if anything exists that suits my needs. I spend a lot (too much) time playing various MMOs, lately it's World of Warcraft. Depending what I'm doing, there's often a need for a large number of key bindings, particularly in player vs. player.
The most natural way for me to play is to use my left hand for keypresses, and my right hand for the mouse. This gives me access to about half the keyboard, so I bind pretty much everything on the left side of the board. I find that's not enough keys, so I also bind ALT-keys, SHIFT-keys and CTRL-keys to get more bindings.
The problem with this is, the most natural digit for me to use for pressing these modifiers (alt, shift, ctrl) is my thumb. Using my pinky to reach for CTRL and SHIFT but my thumb for ALT is clumsy. On top of that, the ALT key is too far to the left to be comfortable while I've got my fingers in the home position.
What I think would be ideal is to shrink the space bar (and put it on the right side of the keyboard), and putting the three modifier keys in the vacant space. This allows me to use my thumb for all the modifiers without having to fold it under my hand. I use an MS split ergonomic 4000 (I know, it's not mechanical - give me a mechanical ergo keyboard please

).
I've looked at the Kinesis, and it is tempting - the thumb keys look pretty good. I'm not sure there are enough keys though. The Maltron 3d looks like it might be more suitable, but the price tag makes me want to be able to try it out before shelling out the cash.
If anyone is familiar with the Nostromo n52, something like that would be about the right form-factor if it had thumb modifier keys rather than the joystick crap they attach to it.
Does anything like this exist, or has anyone done something custom like what I'm looking for?