Ok, I am on my way to being bitten by the camper bug however I dont want to go down the VW Transporter route or the full window/curtain conversion either.

More a normal van- Toyota Hiace with a single bed each side of the van that folds out. One end a storage facility and sound proofing allround.

This way, it would be easy to strip, convert back and sell on? The ply-lined vans would be a easy place to start? Already lined (i.e. soundproofed)?

No need to strip it to sell on. Stick some alloy wheels on it and sell it to motocrossers.