Michael,
With all due respect to the great mechanics out there, regardless of how much they charge for labor, I'd make a few calls first to the local foreign auto parts stores in your area, and see if they send them out. IMHO, that's the way to go. If your mechanic is charging $110 an hour for labor, I don't think you could rebuild the calipers you have for less then replacements.
Why a brake rebuilder? A firm that rebuilds brake calipers usually does that as a specialty, thus has all the proper tools and experience to do it well; do it fast and efficiently, too. They generally follow a procedure and your brakes will come back not only performing well, but looking good too.
If you want to do the work yourself--meaning removing the calipers and sending them out yourself, you can try the following places:
http://www.goldlinebrakes.com/index.htmlhttp://www.brakewarehouse.com/remanufactured_brake_calipers.asphttp://www.whitepost.com/Remember the White Post folks specialize in sleeving in stainless steel, so this alters your brake caliper forever--but it might make it last forever as well.
When mine were done, no finish was applied to the raw casting--it came backing looking like new raw cast iron--and rusted very quickly on the car. Today, you can probably have any color you want (if that floats your boat)but if you want to be more appropriate, a clear satin powder coat on the casting will keep the caliper looking good w/o rust for a very long time. I have to rub mine with manifold dressing
http://www.calyxmanifold.com/ which "restores" the color and keeps the rust off the caliper casting.
Hope it all works out. You can't run a car with stuck brakes!
Michael Salemi
1969 280SL
Signal Red 568G w/Black Leather (Restored)
President, International Stars Section
Mercedes-Benz Club of America