@Graham: if someone invests $1000 into a moped which isn't hard if say you buy wheels from Europe , adds new kits , carbs , cranks , whatever ...you should be able to list what's been added and expect a fair percentage of that in the selling price without being ridiculed.
Plus why encourage fragmentation. Sure there are regional price variation and local pick up is the best , but without repair the buy sell is simply not used and then Facebook becomes the new moped army. I say that's undesirable.