Using a physical MC68B45 would be difficult because of scarcity, while using off-the-shelf devices would be difficult for reasons of packaging and technology. The way to do this is to examine, in detail, all the alternatives, and then build something suitable in programmable logic, the hardware of which is compatible. I mentioned a CPLD in PLCC-84 or some form of PGA because that's an option I frequently use. As it happens there are JTAG-programmable devices from both ALTERA and XILINX that fit this model and are 5-volt devices, and may, indeed, have enough I/O's. As i mentioned, there are numerous evaluation devices that are sufficiently documented that one can give them a somewhat more than cursory examination in order to see whether they are suitable for a given purpose. From that one can also determine whether the approach they use is suitable for that purpose. Drawing "inspiration" from them, one can, ultimately, arrive at a workable approach. Any other source that provides additional information cannot be a hindrance.

RE