Ive been in a similar predicament with my ABF, I ended up changing all three belts, the cambelt tensioner, the auxiliary belt tensioner roller, stripping the alternator, running it with the power steering and A/C pump disconnected.
I even started inspecting other areas including the exhaust manifold, basically it turned out to be an inferior water pump which had only changed about 2000 miles previous.
What kind of condition is your water pump pulley wheel in ?