I'd say it's worth $500 tops. Probably far less as it's missing the unique controller that was pre-changes. Say $300 on bad day.
Not that anyone is particularly concerned, but I did end up getting $1000 for it on eBay. I think that, with a $350 graphics card, 16GB of RAM, a hybrid drive, wireless capability and the novelty of having a numbered test system that over 200,000 people applied to receive, it was a pretty reasonable price. Thanks for your feedback, (mostly) everyone!
I found the prototype (rev 3) controller. Comes the steam box with one or two of this babys? Nice teardown link btw, thanks.