Cool website, I like what you’re doing. I cut my teeth on the 8080 and MC68000 but I haven’t worked with anything but PIC micros for a decade now.
I’m going to keep an eye on your site for updates.
I like the 8085. I think it's as far back on the Intel line as I'd be willing to go with a new system. The 8080A takes more ICs and voltages, the 8008 and 4004 are too demanding for me any more as well, I'm afraid.
However, I've got this nifty Signetics 3000-series board that emulates the 8080A at something like 5-8 times the original's speed. Its single supply at +5V and it breaks out all the signals that are muxed on the 8080A. That I could build a system around...
..once I finish the other two I already have in train.