Good sources for driveshaft repair or replacement part?

Talking with my indy today about the persistent driveline vibration in my 128i, and specifically about the fact that the only thing he found wrong when replacing basically all the consumables from the clutch to the axles was that one U-joint was dry and binding. He lubed it and got it freed, but given that a problem still exists (albeit far less than before) he's thinking the next step should be to replace the driveshaft, the argument being that the needle bearings may be damaged and allowing vibration under load and at speed. I don't disagree. He said basically they've been sourcing new driveshafts, and that may well be the only option, but I figured I'd check in with the hive to see if there were any particularly good places to look for either a replacement unit or possibly rebuilding the existing part. Given shipping costs, proximity to NY is a bonus. Any suggestions would be appreciated.

Could also be motor mounts?

The diagnosis sounds correct. Why not just change the U-joint?  Most "not serviceable" ones are in fact replaceable at least one time.

Freeing up and lubing a stiff u-joint is not an acceptable repair.  It needs to be replaced.  Are they not replaceable on those?

A lot of modern cars have "unserviceable" u-joints. Usually a replacement means cutting off the old and welding a new one to the shaft. And at that point you're building a whole new driveshaft.

Yeah, u-joints not replaceable on these. I don't think you can even get the parts; BMW only sells the complete unit.

Don't think it's the motor mounts, as it's road speed-dependent and only shows up over 45mph, regardless of engine speed.

How much is a new driveshaft from BMW?  I know some mechanical pants can be surprisingly reasonable when compared to things like interior parts.

My thought process is to buy the known good part, rather than install another part only to find out later that it was faulty. You've done a great job of systematically working through a process of elimination, and hopefully this is the last piece!

In reply to dj06482 (Forum Supporter) :

New from BMW is $1230. I do not consider that reasonable.

The last two shafts I bought came from Amazon. Neither one was expensive, $150-$200. Then again they were both for an XJ. 

I would stop by your local driveshaft shop and see what they can do for you. 

LKQ and Ebay have them in the sub $200 range. 

LKQ Link

Ebay link.