Sounds like you want something like the Dygma Defy. It has (I think) 8 thumb keys in addition to the standard keyboard array. It's ortholinear, which I find way more sensible.
Huh, yeah, that's a lot better-looking. It's actually got nine thumbkeys. Still got too few keys though, I already hate having the media control keys and f-keys crammed into two layers on a stock Mac keyboard and this makes both of them into layers on top of the numrow.
Fair enough. The configuration I use on my Corne Keyboard, which only has three thumb keys per side, allows for a ton of controls using just those 6 layers. I've found that it's remarkably useful for coding, writing, and manipulating the OS without needing to contort my fingers/hand in any way.