It might be your local string shop, but it might also be a band department, general music store, or something else. There is a shop that largely specializes in selling pianos, yet has a basement full of all of the theory, history, harmony, counterpoint etc. books that tends to be fairly hard to come by. And the one that I really enjoyed was a small town appliance (fridge, washer, dryer, etc.) place that had an extremely impressive sheet music department as well. Sometimes you have to think outside the box a little bit and ask around, but you might be able to find something in meat space that better suits your needs than online/directly through a distributor.
Michael, I too have printed IMSLP parts, and taped entire symphonies together when I needed to learn something I did not have access to otherwise. It wouldn't be my first choice not only because of the amount of work involved, but also because a lot of the parts online have been reduced from whatever that weird size of paper is that orchestral parts are printed on, so when you go to print on standard paper (8 1/2 x 11" in North America, most of Europe uses metric paper which could also be part of the problem) the parts often end up distorted or smaller than you would like them to be. The other thing I have noticed is that sometimes IMSLP has different editions copied from what you often see orchestras renting, which can take a little while to adapt to if the page turns are in a different place, you're mentally prepared for that thing on page 5 that ends up coming at the bottom of page 4 instead etc. While it is a solution, and a very helpful one in many cases, sometimes it would be really nice to have the individual "real" parts.
As far as a group/mass order goes, I am currently in the middle of a move and not in a position to dedicate the time needed to compile a list of potential parts, collect interest here on Talkbass, and then distribute them. I don't even know where my mail goes at my new place, and would have to look up the address. If you've got some spare time and want to put it together Sam I'd be interested, but I'm not the guy at this point in time.