I think it's a great idea, and should be somewhere like the Garage as a nailed topic so it's found by the most people looking for that info. A sub of Classifieds or VINs might be harder to find than a Nailed Tread in the main area.
Between seeding it with Jeff's, DaveP & the 914-6/GT sites' info., as well as members posting their sales & buys - along with pix & realistic condition statement for their cars, it would be far more accurate than NADA's loosey-goosey running average with no condition info. on individual cars/sales at all!
There's also this 914-6 registry I found before, but very few prices:
http://www.stazak.com/914reg/1970a.htmlThis would no more violate privacy, than the sales on evil-bay, TheSamba, on here & 914club, etc. being searchable, and the fact that DMV's also have sales prices for tax purposes (just multiply the tax paid by the rate in effect & you have an almost exact price - same with real estate).
And yes, it appears that TC has traded & retraded just about every 914 out there - except mine, unless he was an unknown PO between 11/72 & 12/75!