The circuit board, marquee, and wiring harness can all go to ebay. The Arch Rivals joysticks are Williams 49-ways, and were also used on Sini-Star. I love 'em, they're great sticks. You might consider keeping them for your MAME project, you just need a pair of GP-Wiz49s from GroovyGameGear to interface them.
Also, the monitor is a MEDIUM res monitor, so it's not so good for MAME, but they're in short supply on the used parts market, so you might do OK selling that, be sure to get some really good pics of the game running, showing how clear and bright the screen is before your dismantle it.
-EDIT- I was flat wrong here. Arch Rivals uses a Standard res monitor. My apologies to anybody that listened to me. -EDIT-