It wasn't until I read this specific post that I new Tim is proposing this restoration service as part of an existing shop/dealership.
As others have said, I don't think it can stand on its own. However, as part of an existing shop, I see it as a viable, though certainly small to start with, portion of the business. One must carefully and honestly communicate with someone interested in a possible saw restoration, with costs and potential pitfalls discussed in detail. What you're really doing is bonding with the customer on an emotional level. I know, we're mostly a bunch of guys in here, but honestly, you are making a partnership with the customer to bring that old saw back. You better believe someone who will spend $500-$800 or more to restore grandpa's 40-year-old saw is doing it for emotional reasons.
If each job is painstakingly done, with before-and-after photos taken, and with a growing list of satisfied customers, over time the shop will develop a reputation for this kind of work. Why the pics? For the saw restoration Web site, folks, because that and great word-of-mouth are what will get the news out there.
And really, there's very little financial outlay in offering this kind of service at an existing operation. So why not?