Thanks for the replies and support, guys.
I found the estimate, and there's NOTHING on there about any kind of fee should the customer back out of the contract, so he was just trying to intimidate me into giving him the job. I did sign saying I agreed to have them do the work, but there were extenuating circumstances and he acknowledged I was not hiring ANYONE until I'd gotten several more bids.
So, I guess he could sue me for $1700-3400, but I can't imagine he'd win because we won't allow him on our property to do the work. I don't think one can win a contract case when they haven't done any work and there's no clause in the contract awarding them damages should the other party default on the contract. That's why I have my own clients sign a contract that gives me recourse should they cancel their appointments or terminate my services without sufficient notice.
Anyway, I'm not even worried enough to talk to my lawyer friends at this point, but I suspect they'd tell me I'd likely win in court given the facts. I just never would have imagined I was signing a contract for him to do the job, but I'll certainly be extra careful about such things in the future. The guy we'll be using does have a separate box for the customer to sign in order to accept the bid, which I'll be happy to sign when he comes to do the work, but he didn't ask me to sign it when he gave me the estimate!
I don't have a problem with not getting a written bid, but I would want something in writing prior to them starting the work so there aren't misunderstandings about what should be done or how much it will cost.
I told him his best bet was to let this go, as I'd be less likely to share my thoughts about his business practices all over the Internet, but he said he didn't care if I did since he had plenty of customers already.
This guy's a liar and cheater all around.