The download page at 36.dauug.org has an electrical simulation for the 36-bit system (in with the same tarball as everything else). It's slow, since it's designed to catch timing issues. About 23 hours of wall clock time gets 1 CPU second simulated. The RTOS kernel also runs in simulation with preemptive multitasking. It's not ideally packaged because it's not as far along as I would wish.

There is a virtual machine for the 18-bit version, really not ready to release yet due to some gaps, but can be provided to you offline.