Just my .02 ...
First, check out BBoAH, look at A1200 accels. I am biased towards '060's, but, yes they are pricey... Depending on the apps. , an '030 w/ 8MB, or better 32MB would do nicely. My dad ran a similar system for DPaint5, PPaint, TuroPrint, for years, with frequent breaks for pinball games
:-D