I know that feeling Bob!
I got hooked on TB 1931s a couple of years back as well. And yes, I too have one on my LokProgrammer board. The 1925s that I used to think were the bee's knees sound a bit lame after that. I have TB1931s in my Atlas MP15DCs and C-424, OMI MP15AC, C&LS RS-11s and 32s. My P&D F7A and B have TB1942s now. The chassis are basically a speaker with a truck on each end, thanks to the space created by using Jay's dual-motor drives.
Somewhat ironically the only locos I haven't been able to cram 1931s into are my RC GPs so I am very keen to see how your cunning plan works out!
Pete