IME, although the hub may be an issue, i have found that the "spin in the fingers test" is not very conclusive. i think that the discrepancy in forces between the fingers test and those in use are too great to warrant any definitive conclusion.

cartridge bearings are pretty inexpensive and sometimes can even be found at the local hardware store in lieu of the LBS, at an even greater savings.

i think i'd try a new set of cartridge bearings...

but there are really two alternatives i see off the top of my head. (1) replace the hub and all costs assiciated with doing that and accept the fact that you will never know what the real problem was. or (2) buy new bearings and risk having to do option one anyway.

i don't suppose the bearings in the front hub could be used in the rear hub to limit the risk of option 2 (which is the cost of the bearings) by any chance? you could then have your cake and eat it too. could you be so lucky or could it be so easy?