Well, I might as well post something here to let anyone looking know. I have started working on this project again after several years because when I got the new board for my TrapKAT (having had the old on die), it came with the V4 chip. So now I have to get V4 support working!
V3 users need not worry. I already have the scheme for conversion back and forth between V3 and V4 implemented. There's still a long way to go before I have a version of the program that I'd consider "safe" but the source code is available for anyone wanting to look.
I'm also planning to ensure the program runs on Linux under MONO. The aim here being that, if it works on Linux, there is no reason it shouldn't work on OSX. (I can hope...)
Oh, and it's got more colours.