Well, I picked this sucker up a few months ago thanks to a tip from Peale:
http://www.gis.net/~tower/arcade/tank2/That's the exact condition I got it in. I haven't really had the chance to do much work on it, but it's in a nice safe and dry place in the meantime.
Well, yesterday I finally got around to getting a bit of work done on it. I met up with Peale at an arcade auction (bleh on the auction) that wasn't far from my house. He came over afterwards and took some shots at bringing the cab to life. He reseated and cleaned off some of the socketed chips, poked at the monitor, reaped a PC power cord to replace the old sporadically shorted cord that was on the cab. Not a ton of progress, but some good troubleshooting and at one point he did accidentally manage to make it throw out an explosion sound.
At this point, we have light in the marquee, the PCB is clearly trying to do something, and we have light (but not game) in the monitor.
Much thanks to Peale for the assist.