I ran across a reverse engineered copy of Extended Color BASIC (mostly just Color BASIC actually) that had been ported to other 6809 systems.  It's been sitting on my hard drive for some time but I had forgotten about it.  At first glance, the math library appears to be very similar to Microcolor BASIC.  I could probably squeeze several changes from my MC-10 code in, but I'll have to locate a more intact version of the original ROMs if they exist.  There are also a couple things I could borrow for the 68hc11 and 6803 versions.