Thanks, waybomb.

Quotes are in. All include one year parts only warranty, replacement torque converter and $400 for my mechanic to R&R it:

1) used tranny with 89K miles = $3200
No way. Not for that price and that many miles.

2A) phoenixhardparts.com remanufactured = $2650 to $3400 depending on core evaluation.
They don't have it in stock but can build it quickly. Problem is it will take up to 10 business days (if no delays) for them to deliver it.

2B) europeantransmissions.com remanufactured = $2840 to $3590 depending on core evaluation. It is in stock in Atlanta and could be delivered by Tues (Wed at the latest).
I am leaning towards this option.

3) rebuild by the mechanic 500 miles away = $4200
He says he knows about the $2100 assembly for rebuilding it and he factored that into his price.

4) Mercedes remanufactured = over $6000 (sorry - don't have the exact figure -- left my notes in the office)
I can't justify putting that kind of money in a truck that isn't worth $10K after the repair.

I am really leaning towards 2B. Even though I trust the mechanic who is working on it, he is 550 miles away and it will be difficult for me to get warranty work from him. If the remanufactured part fails in warranty, a local mechanic can R&R it and I can deal with the Atlanta company from home.

Any suggestions?