Beaky found multiple sound issues (humming) on some of the Rottendog boards, and even had Rottendog send him a brand new board to replace one of the ones that was made in a faulty batch. I know Andy reckoned the older boards were made better etc. You are right, best to find a good second hand board if possible.
The only person who seems to come up with good 2nd hand stuff is Jeff from Classic Arcades USA.
Also, You could also ask for Arthur, who works for Wayne Gillard in Melbourne. Arthur has alot of pinball parts going back many many years. He would be worth a try.
Even Mark might have some spare boards sitting around. I would even check with Rob from Bikecity, also in Melbourne. It really pays to ring around to all the local guys.
Ya just never know who just might say YES, got one.