I think it would be an interesting project to make a board that connected a microcontroller to that Opto22 board. I've also been looking at bus transceivers, latches, and multiplexers. I'll have to order some chips to experiment but it might be easy to get 32 (or more) I/O from a BS2. The idea is that you have multiple 8 bit chips, some for input, some for output, the 74XX138 selects to enable 1 of 8 chips based on the binary address inputs. The outputs latch what the BS2 outputs, the inputs enable to read that selected input. The program would do something like read the inputs, process the logic, write to the outputs. There is an output enable on the latches so you can turn them all off at once if desired.
I've been interested in investing some money in a project this year to try to see if I can make it grow, Basic Stamp and MicroController to Opto22 boards might be an interesting investment. I would like to see what's required for in circuit serial programming(ICSP) so users could program from the USB port. I'd also want the Basic Stamp to be programmable without removing from the board.
RogerN