Wiring harness fried!!! Help or name of good mech in Vegas!

I don't know what happened! I bought my 850 in August, everything's been going pretty well, until Monday. Monday I was driving home and started to smell something coming through my vents. By the time I actually got home, I couldn't figure out what had happened. Tuesday I drove to work - everything's fine. At lunch I had gone less than a block, the smell returns with smoke. I stop, open the hood - there's smoke coming from the wiring harness, and it's coming from everywhere under the hood.
I don't know how much damage has been done other than I can see several wires that are now a melted together mess. Today I towed it to the BMW shop and they told me it will cost $3400 for the harness, $5900 if they have to replace the computers too. Has anyone had this happen? What's the deal? Also, I'm in Las Vegas, NV - anybody know a reliable shop here that might not charge me so much?