How can I find inexpensive salvage repair (frame) parts? I've got a 2008 or 2009 Titus X. I cracked one of the struts (probably the wrong term) in the rear suspension triangle.

I'm hoping I can find a salvage part (still waiting to see how expensive a new part will be if it's not covered under warranty).

My first thought is Ebay but I thought there might be better places. Is there such a thing as a "junkyard for bikes" by mail? How can I find where to look for salvage repair parts?
For this bike you may be able to get replacement seatstays or chainstays from the manufacturer.  See their frame parts section of their store or give them a call.  

http://shop.titusti.com/category-s/1836.htm