Greetings,
Your options for tweaking Soft Key appsets are as follows:
(1) EuconLayouter from Sonic Monk:
http://www.sonic-monk.com/euconlayouter/index.shtml
(2) XML Editor. Modifying, copying and pasting chunks of code on a larger scale.
(3) Manual Editing.
All of the icon bitmaps are 72 DPI with an average of 55x55 pixels. With that said, icons can be as wide as 175 pixels and as tall as 70 pixels.
Jeff