I didn't try unidasm with the COP400 myself, but I can see it supports COP410,20,and 44 so in theory it should work.

Entex Turtles and Stargate work fine on MESS, added them this morning. These games have the Hitachi MCU, and a COP411L for handling sound. (oh, still need to add the gamespeed knob on Stargate)