if you are near a major city, i recommend craigslist.

you mentioned you are an engineer, so am I. we can figure out if a bike has been structurally damaged. I bought my 08 Felt F1X (retail $1500) for $450 because it wasnt shifting right and the spoiled kid that sold it to me just bought a new road bike (about $3k) and didnt want to hassle with it. it took me 2 minutes to tweak the front derailure and its running like new. A benifit of living in Orange County, CA. A couple million rich farts with awesome equipment that go out and buy new stuff every year.

be picky and patient though. by definintion the asking price is too high! alot of people have an emotional attachment to their bikes and want top dollar, bring reality with you. the price can only come down!

oh, yeah, thanks to craigslist i also scored about 260$ worth of brand new topeak equipment (MTX rack, bag, and allay race 2.1 saddle) for $110. I want to support my LBS, but i got student loans, man!