We had a similar plan a while back (before the @rse completely fell out of the motoring market!)
Wanted one car which would do all the things we needed; carry us, our son and all required baby paraphernalia, and fit the bikes and trailer in/on it, and as we’ve had a few more involving/less practical cars in the past, still be fun to drive. As we do very limited miles (neither of us drive to work), and petrol prices hadn’t got to the ridiculous levels of late 2008, we weren’t excluding less economical cars.
Test drove a fair few cars, including RS4 Avant, RS6 Avant Supercharged Range Rover. Also considered th M5 Touring. I soon realised that any car would be a compromise, and would not feel as nimble as a smaller performance car. That’s why we looked at 4x4s. Hated the image but as the bigger engined models were dumping money from new, you could get a lot of kit for your money.
RS4 was surprisingly small inside, and the RS6 (it was the old model as the new one hadn’t been launched) was fantastic to drive although looking a little dated on the interior. Range Rover was great inside but was like driving a boat compared to our previous cars.
Got persuaded by my wife to test drive I Porsche Cayenne. I didn’t like them as I thought they’re pretty ugly and hate the image. Was very pleasantly surprised. Felt like I was sat in in rather than on it. Interior was functional and similar to smaller Porsches I was familiar with. Performance was surprising. Masses of straight line acceleration and very nimble in the twisty stuff. Ended up getting the Cayenne and we’ve been really pleased with it. Picked it up second hand for just over a third of its list price. Still think it’s quite ugly but then we spend most of our time on the inside rather than the outside. Surprising off road performance- handy at the quagmire that was SITS last year!
Looking at your original post and later comments, I say that at the moment you need to be prepared to take a real hiding on the resale value of any performance car at the moment. They are haemorrhaging value. If I had my time again I’d likely go for the Cayenne again or an M5 Avant. If you are completely against a 4×4 fair enough, but I’d say test drive one of the faster Cayennes; you’ll be surprised.
Ideal option is have 2 cars; an Elise or Caterham (which will probably lose less money) and a more practical ‘work-horse’.
Good luck shopping and test driving. There are certainly bargains to be had!