Couple of things.

I would think that the sweet spot for publishing anything would be proportional to the size of the press in use. So choosing who you go to will make a difference. I mean, if you have access to a press that is web-fed it will have a lot of play in abilities (though these guys only deal LARGE volumes due to the equipment operation costs), but if you go to a local mom and pop printer that can handle a 17x22 sheet you can still get a better price then say single page printing source.
You talked about page count but not page sizes, which will directly affect the number of pages the press can squeeze into a parent sheet, so you may want to think about that as well since the number of cuts will increase price.

Check this out for some ballparking
http://www.printindustry.com/printing_quote_for...

Additionally, I would recommend talking to a local community college (one that does desktop publishing courses) and see what they can do for you. That is a real world experience that they could use as a teaching tool and I know when I suggested to my teacher to print a homebrew setting book he was thrilled with the idea.

I personally recommend Ventrillo for group conversations. Just my 2 cents on that one.

Ed, I found the discussion regarding the page count 'sweet spot' very enlightening and I'm interested to hear what you find out. So far, looking behind the screen has not diminished the appreciation of the end product. I always knew a lot of work went into them, and now you are helping to quantify that work for everyone to see.

As someone who hopes to someday publish a game-related work, this is very educational and will probably serve as an excellent 'must read/hear/see' primer on the subject of RPG publishing. Thanks for doing this experiment in transparent publishing.

JJ

This is forcing me to test and quantify things that I might, if not doing it openly, not take the time to properly analyze. I'm looking forward to actually poking this with a stick and seeing how it reacts.