I've had it done at Duggal in New York. They have 11x14" racks for their dip and dunk lines. They don't list it in their standard services, but if you ask, they'll do it, and the charge is not unreasonable, compared to their other sheet film rates. I think it was something like a bit more than $6 or $8 a sheet when I last had it done a couple of years ago.