This isn't really viable. Why would anyone want to use their old bodies? I mean yeah my Nikon FE is a metal beast that is endlessly reliable, but in terms of features the latest digital bodies are ergonomically and technically superior to the old bodies in every way.
A 2008 GT500 is probably ergonomically and technically superior to that of a 1967/8 GT500. Please explain why the 60s GT500 in restored condition fetches a $200K+?
Please explain how Leica was able to sell a $5000+ M8 rangefinder that has its roots and basic technology tied to a camera designed in the 50s?
How about watches? By your standards the basic Casio digital watch is superior to that of a Tag, Rolex, etc... hell many are still windups. The most expensive watch in the world, Vacheron Constantin, has a "low-tech" analog face.
There are 100s of reasons why one would want to use their old mechanical bodies..... the simplicity.. the reliability of the mechanical clock-like movements... the pure enjoyment. Yeh.. they are technically ahead of the game with the fancy CCDs and CMOS sensors but "superior".. by who's definition? There are some of us that don't equate updates to ergonomics and technology to the enjoyment of photography.
I think if someone produced a 6mpix digital version of the student K1000 with the same build and simply controls for under the cost of a P&S, it would sell like hotcakes.... The used K1000s are still being fetched up on
ebay even now. I know i would buy one... I even splurged on a Samsung 6mp Pentax copy from a pawn shop just so that I can have a digital companion to my K-mounts and screwmounts.
In the end... though.. I agree. between scanners and low cost DSLRs... it really isn't cost effective..