It looks very nice! I'll try it. And I have sugestion for you - it would very nice if your simulator could accept some kind of data from file and output some data to another file. The idea is, that you write file with data witch should be passed to some port. Lets say, you want to simulate 8051 work with parrallel ADC. So, you write, let's say, in hex format values, and adjust simulator to pass those values eatch 10 ms to P1.

I hope idea is clear enought...