Some models (e.g., the 150) supported Multibus. In the early 1980s at Tandem Austin we used one with a SUN graphics board in a Multibus slot to prototype a 68000 workstation we were building (but that never became a product). Al Kossow has lots of information about Wicat in bitsavers. Here’s a brochure for the 150: http://www.bitsavers.org/pdf/wicat/brochures/System_150_Brochure.pdf