Personally i've been looking into whats required to become a car dealer. e.g. go to auctions, buy cars, sell them on. It's like my dream job! Not looking to do them up or anything, just detail them and advertise them for sale. I've got a large driveway and can fit 4 cars on there, so it would be a starting point... i wouldnt necessarily need a lot.
i've bought quite a lot of used cars over the years, and i always get talking to the independant dealers and it sounds perfect for me. I sit on autotrader just watching car prices in my spare time anyway, so i feel like i've got the knowledge to start me off in the industry. Even if i only sell 1 or 2 cars a quarter its a start... the best thing for me is i can do it alongside my full time job. Imagine that your job was to do a bit of googling to find a car, hop on a train to go and pick it up, then drive it home and prep it for sale. Depending on your target market you could be driving a different high-end car every week... Range Rovers, Mercs etc...
Maybe something worth considering.