I don't think of your emulators (thanks, by the way) as strictly being interpreters so much as splitting the difference between interpreters and HDL simulators. In some ways it's like you do high-level behavioral simulation of internal logic and RTL at the bus/package. That whole problem space is a far cry from running some Mac applications.

Architecturally, I think some of the things you want exist in some unusual microcontroller families (XMOS, GreenArrays, Cortex-R), but then if you get to pick the microcontroller I guess you might as well also pick the clock so that you can run in real time instead of simulated time.