Thorn Sherpa, Co-Motion Custom Road, Salsa Fargo, Mercian King of Mercia and Motobecane Fantom Pro 29er
I am pondering the same question w/ my LHT. Having a hard time spending $400 on couplings when the frame cost that much. However the alternative, a custom bike w/ couplings, is out of the question.
Whatever it's worth, Bilenky has the best price for adding couplings and have done more retrofits than anyone else. If I decide to do it, they will be get the job. When I called last week, they had just done a Surly.
I have never heard anything negative about adding couplings. The only thing is, is that it will void your frame warranty but with Surly, that's only 5 years anyway.
I suspect that there are a number of framebuilders that you could use to put the S&S couplings in but I would definitely recommend Bilenky. They did a fine job on my 1982 Mercian. They're in Philadelphia but UPS goes everywhere!
Hey, I *just* did this to a LHT frame. Beware, there's a small snag with the process. The top tube is ovalized, and it makes putting a coupler there difficult. Bilenky said they could do it, but two local frame builders (Bob Brown and Curt Goodrich) suggested replacing the top tube as the best way to get the job done.
I did quite a bit of research when I started this project, and never once did I find a picture of a LHT with couplers online. Not saying it doesn't exist... but I couldn't find one before I put up my pics. Now there are several though!
Curt Goodrich (Riv frame builder) did the work. He replaced the top tube, the dropouts, installed the BTCs, and changed some of the cable-guide braze-ons. I didn't work with him directly; my local bike shop (Calhoun Cycle) has a relationship with him and they sent him the frame.