CPU in circuit emulator
Get a PCI style FPGA board that you can use generic IOs for the target 68000 connection. Implement your control system in the FPGA, and write software to tell it what to do. That's basically making your own ICE kit. If the commercial ICE kits are horrendously expensive (check and find out if they are, I don't know), then this could potentially come in cheaper, and give you control over how it works. Check out Raggedstone, Broaddown or Mini-Can FPGA boards, they are relatively inexpensive boards, but not sure if it has enough accessible IO pins for what you need. Then check OpenCores for open-sourced PCI blocks and other things that may be useful. You may also need to add some level shifting stuff on a small PCB addon to these boards. Look up Xilinx/Altera white papers on using Quickswitches between 3.3V FPGA and 5V PCI, hooking the other connections to a 5V 68000 socket would be essentially the same process.

As I remember, the DIP 68000 is 68 pins, and some of those are not used in some systems, such as Amiga does not recommend using some of the 6800 style peripheral pins, and they become disconnected in later Amiga systems.