I have written a small tool to create drum maps for Sonar from an instrument file (or any other text file with lines "note=instrument"). I always found the initial step of adding all the instruments to the drum map the most tedious, with this tool it becomes almost copy/paste if you have a textual description for the mapping.
You can download the "instrument to drum map" tool from my new web site
Audible Distortion under "Tools > Cakewalk Sonar". There are also several other just released tools for musicians like an SysEx editor for the Novation Impulse keyboard, musical calculators, and a waltz generator that creates over 759 trillion different waltzes based on a dice game by Mozart.