You make me miss all my C-128 and 64 stuff sometimes. I had everything CMD made and 2 or 3 of each. I sold most of the desireable stuff on Ebay 2 or 3 years ago. I just had to make a decision which hobbies to keep and the Amiga and the Corvette won, and my 128 & 64 stuff lost. When you talk about the speed of doing things with the Super CPU & Ram Link & CMD HD I know exactly what you are talking about. I beta-tested most of Maurice Randall's Wheels and other GEOS stuff.
What made me give up on the 8 bit stuff was the inability to do anything to improve graphics. It was built into the computers with no way around the bottleneck. With my Amiga I can still put a jpeg picture on my computer screen and it looks every bit as good as it does on a clone. Your C64/128 set-up can't do that. The best you're gonna do is an interlaced picture on a 128 with the Lace II viewer. Don't get me wrong, I was into everything Commodore 8 bit for almost 20 years and had built up a massive collection.
I still have somethings to sell but it is mostly common, heavy hardware. I do have a couple of 128D's to sell including my super-duper one I used as my main 8-bit. It had internal stereo, internal cooling fan, a programmed chip in the empty socket, jiffy-dos, an internal rom and switch to change the screen font, switch to change internal drive address, and several other modifications.
Dan