That is a good idea. Here is the MTGAP keyboard in lower case, minus the touchpad area (You could stick the touchpad part on either side). I'm not sure about keeping the Print Screen/SysRq and Pause/Break keys in the upper right (it's rare that I hit them, except by accident), but I'm keeping it for backwards compatibility.
Show Image
(http://geekhack.org/attachment.php?attachmentid=42048&d=1330442617)
That looks pretty neat!
Staring at it for some reason I felt like comparing MTGAP to the Malt layout, and noticed a few similarities with the off-home columns (V, D and B).
(http://upload.wikimedia.org/wikipedia/commons/thumb/5/56/KB_Maltron_3D_US.svg/1337px-KB_Maltron_3D_US.svg.png)
Also Malt has the extra letter F in the home row, while E moved to the left thumb.
And now I'm wondering how a normal keyboard layout can be modified to make use of an extra letter on a thumb (whichever thumb isn't pressing space). :)
The idea of using the thumb sounds fascinating, however changing keyboard layouts again doesn't sound so appealing. If Colemak (or other layouts) could be modified to make good use of a thumb by swapping just a few keys, that'd be quite intriguing.
Update: Sorry for the slightly off topic post BTW. Found Optimizing the Maltron layout (http://forum.colemak.com/viewtopic.php?id=994) over at the Colemak forums, where he attempts some Colemak Malt-ification. ;)