It is rare to have more than one cause of failure at a time. It happens, it's just not that common.
So has SCSI Bus 0 or Bus 1 failed? The one that resides in the MESH chip, or the one that resides on CURIO?
If it is on CURIO, that is not too hard to fix, as the CURIO chip can be stolen from any other machine from the x100 family forward through the entire Power Surge (X500/X600) family. The soldering looks intimidating, but it can be done with a bottle of flux, desoldering braid, some modeling clay, a heat gun, and 40 and 15 watt soldering pencils from Radio Shack. Oh, and some dental picks and a stop watch don't hurt either.
If you don't have the heat gun and such, the tools quickly outstrip the price of the board though. Heck, just the shipping cost to send it round trip to someone who can do the soldering is a pain. Still, you might check with Mike Richardson, present on this board, and see if he'd take a hack at replacing that CURIO chip, if you're pretty certain that's the problem, and assuming the washing doesn't fix it up. I'd offer to do it, but I just don't have time. I still owe a nice fellow in the UK a ROM DIMM assembly as it is...