I would think 68000-based games could be reprogrammed to run on the Saturn considering how many ports there were of games running on that hardware.
One issue with the Saturn is that there were a significant number ports of Genesis / MD games and Neo-Geo games.
* Sonic 1, 2, 3, Sonic & Knuckles
* Thunderforce 2, 3, 4 (Japan Only)
* Quackshot & Mickey Mouse (Japan Only)
* Phantasy Star II, III, IV (IV only in Japan)
Neo-Geo (Japan Only)
* Fatal Fury 3 (doesn't use memory cart, may be missing a few frames)
* Fatal Fury: Real Bout
* Fatal Fury: Real Bout Special
* Samurai Shodown III (not as well programmed as IV, misses a few frames of animation)
* Samurai Shodown IV
* Metal Slug (two revisions)
* Galaxy Fight
* Waku Waku 7
* King of Fighters 95, 96, 97
* Samurai Spirits RPG (different than Neo Geo CD version)
* World Heroes Perfect
Unlike the Playstation versions, these were virtually the same as the Neo-Geo counterparts (as long as people used the correct 1 MB SNK memory cart instead of the incompatible Capcom memory carts)
That leads me to think those games (being 68000 based) would not be too difficult to reprogram or recompile for the Saturn.
According to Electronic Gaming Monthly in the mid 90's, SNK planned to move from the Neo Geo CD to the Sega Saturn, porting the majority of their titles, including Pulstar. However, Bernie Stolar's premature announcement of the end of the Saturn put the axe on that.
I'm ignorant of programming and realize there was no Z-80 in the Saturn, but as the sound in the ported Sega Genesis / Mega Drive games appears intact they must have had some easy way to run the sound with one of the RISC CPUs.