I'm pretty sure I have a line on a nice 64c, after I get that squared away I'll be ordering it. I should have the parts to fix my 1802D next week, too...
I figure depending on the sounds I want, I can switch between the 64c and the C128... might even run SID2SID boards in both.
I can't wait... for me, this has been one of the most exciting computer related projects in years. I'll link to some pics once everything is up and running.
One thing I'm finding though, is that short of buying whole computers, SIDs are a little difficult to come by, which makes this process a lot more time consuming.