Quoted from swampwiz:
I noticed this listing, which claims to be for a new MPU. It looks like an OEM, and not an Alltek.
ebay.com link » Brand New Dash 35 Mpu Cpu Pcb Bally Pinball All Chips Socketed
That guy is a good man and has been around for lots of years. If it were me I would buy the aforementioned one. It's a one size fits all model, gotta' love that. My only problem would be that I have a rough time selling games with prized PCB's in them.