The two processor stucture of the Saturn was a really bad move, well commercially. Sega first created the ultimate 2D system, but when they saw the PSX specs they threw in a new processor. The only ones being able to do somthing with those processores were AM2. Nevertheless developers we're lazy, including Sega, instead of creating an arcade perfect port of House Of The dead and Virtua Cop 2 they opted for reusing older engines. One of the best conversions was Last Bronx, with 3 dimensional backgrounds and the high resolution mode in game. They didn't take the time to perfect teh shadows though. But then again, Saturn never was a model 2 system.
Oliver Galibert, I was wondering. As you are one of the two creators of the Model 1 implementation in Mame you are the right person to ask this. Why isn't there a website where the two of you post your progress? A place dedicated to the great work you guys are doing would be great