part availability/remanufacture

I'm normally a cynic but I'm optimistic about this one. Things will become viable for re-manufacture if there's a market for it, and I believe the exxy will be popular forever as a design landmark and a practical proposition. Where there's a market they'll be people willing to service that market, so I believe we should be OK...and with the occasional bit of ingenuity (See Canadian Tony's posts/articles in the past) we'll be OK. I'm in the same boat as you Jim, I've loads of spares that I'll probably never require, but give it a few years and the club will be able to muster hundereds of orders for those often required widgits and re-manufacture will be viable.
The bits that will be difficult will be the plastic trim parts, and hoarding them will be pretty pointless as the plastic will be quietly degrading away in the shed, and when we do come to require them they'll be crumbling to dust. Look for all those bespoke interiors in 20 years time!