Dan,
We have something like this out in the SF Bay Area where we live. Some of the info is good and you can try it. For buying my TCH, my husband prefered to work with a friend of a friend who is an auto broker out here. While the deal might not be as good as one we negotiated at the auto dealer, my DH was happy to pay someone else to get us a good deal and avoid the dealer hassles. And since my DH was paying for my car...

We were so pleased with our broker, that we are using him again to get my DH's 07 Prius next week. So by this time next week, we will be a 2 hybrid car family! )

Check around with your friends and family to see what they have done... you might auto broker in your area that will do the negotiation part for you at a price of course...