Check with www.go-ride.com. They're Giant dealers and have a strong relationship with the company, especially for finding some older (slightly) stuff. They are my fave LBS here in Salt Lake, but they also do a ton of Internet business so shipping would be a smooth process. Their main telephone number is 801-474-0081 (they do have a toll free number on their website). Ask for Kris or Scott and tell them Mike Power sent you. They will do their best to take care of you. I would suspect you may even have a warranty available also, but I don't know Giant's warranty policy on frames. Hours are 10-7 M-F, 10-6 Saturday, mountain daylight time. Call during the week because both Scott and Kris usually have weekends off.
My first stop online would be eBay but you can even just do a google search--start broad then search within your results to narrow down. There are a lot of places on the net where bikes and frames and parts can be found for sale, so why not let google do the work? I would also suggest checking with Giant directly. You never know what they might have sitting in some dusty warehouse corner (that they would be happy to price gouge you on).