Belgium traditionally is good for cars because there is no domestic auto industry to protect. I've done lease-buyback deals with pickup and return at BRU airport, right in the rental car area. IIRC the initial period is limited to six months but it's easy to extend. Beyond that, you can actually buy and keep the car, to resale when you leave Europe, but this is more hassle.

Another idea is to arrange for a European delivery new car that you take home with you (on a ship, which is all arranged for you) when you leave.