Just throwing out there a couple of random name of machines to see if we have all the roms/resources for them and if they can be done or are being done.
Throw a Wobbler, see one being sold on Ebay. Been asked for a few years back, but no roms available then.
Thru' The Roof, I see this listed amongst fruit machines roms for both Ace (sp.ace) and Ace (Impact)