When you say "vinyl clad", do you mean the off-white vinyl that was used in the 70's trailer, or a clear vinyl so that you get a coated, shiny appearance similar to the CCD models of today?
If it is the former, then you probably are going to have to get used skins from trailers that have been refurbished with new, shiny aluminum skins, and try to retrofit them.
If you want new, shiny interior skins with a plasti-coat like the new CCD models, then you have two options.
1)You can buy that very aluminum from Airstream dealers. It is freakishly expensive--seems like I was quoted around $250 for a 4x12 sheet.
2) You can buy raw aluminum sheet and then try to wax it or paint it with a clear coat to keep every fingerprint from leaving a mark. I can buy the raw sheet in a 5052 for about $60 for a 4x12 sheet. I just bought 9 sheets to redo my interior. Haven't figured out the clear-coat part yet for sure.
There is another thread along these lines here: