With your skills I think that you could be more ambitious than that, think about a Fiat 126 campervan conversion more in keeping with the 126 design and shape of the car. Something that looked like it was original, standard and factory fresh. Probably a one person campervan, something that someone could do a long road trip in. It would need additional storage space using both the roof and interior and also a sleeping space which could be achieved by removing the passenger seat and making use of that space. Cooking facilities would need to be used outdoors and washing and toilet facilities would need to take advantage of external options like e.g. using a sports centre. What do you think? Could it be done? BIS would probably be easier but aircooled is probably the real puzzle to solve.