Any model and year specific parts are going to be an issue, especially if the model run was only a coupe years (or less) long.
Electrical and mechanical switches are going to be the things that will bite you. The more you really don't want to have to modify to get something to work, the more parts your going to need to stockpile (70s Dodge truck heater cores?).

The more common things you have a chance someone will reproduce, but I suspect things will become a single offering that is suppose to fit many different applications, which comes back to weather or not you want to modify something to work. Gene