Having just returned from a ride on my '62 PX-10 (too early for Delrin!), I nominate her as having one of the more unusual colours which I think was only offered this year: chartreuse green (think of a Peugeot painted like a Legnano) with vermillion lugs lutlined in black. Actually quite striking looking and almost British club bike in its boldness.
http://www.wooljersey.com/
This same colour was used on the PX-50 model that year which is shown on the Retro Peugeot site:
http://home.wanadoo.nl/
Oh, by the way, I'd never pay $3500 for a PX-10. Well maybe one of Tommy Simpson's. Indeed, the object is to pay as little as possible and enjoy the machine as intended: a simple, straight-forward no nonsense pure racing machine for cheap.
Peter Kohler
Washington DC USA