Good one... hmmmm.
Depends on how many kids i guess. I would search out a 00-03 BMW M-5 (20-25K) do a little suspension work, a chip or some ECM programming and enjoy. They make a belt driven charger for them but IMO thats a bit much. It doesn't have 10 computers in it either. I have a 535 with 247K runs like a champ (looks like crap), heads and bottom end have NEVER been touched, it's been my daily driver since i started MAC. I tought my kid to work a clutch in this 535. Brother has several BMW's a hot 540 (serene at 140 mph and still pulling) a couple 745's and a 760. The 7's are cruisers, the 5's with a little more motor are the way to go, I can't drive past the car neither can my Bro, it'll squash you to the door panel and the back of the seat.
Never seen a Vette, EVO, STi, Mustang, run as hard and dependably at 140,000 miles as they did with 40,000... does a Vette not squeek uncontrollably at 25,000 miles?
Good luck whatever you choose, sounds like a great idea.