Alright, I think my PX-10 could be on the way toward being the kind of rat rod the OP is looking for: truly beat up paint; Mafacs upgraded to black Kool Stops; Campy FD, shift cable stops, and pedals; and Suntour barcons. For now, I'm just getting it tuned up (although I may try to clean up the paint in the not too distant future), and I may throw some Mavic/105 700c wheels on for fun and maybe replace the RD with a 105 for a while to see how that works out. Some HG cassette is almost certainly in its future.
So I think it's got the look, a smattering of upgraded parts, and it's lightweight and a good ride. Of course, motor upgrades are still in progress...
Close ups to show the awesomely ratty condition of the finish:
