Sounds silly but have you thought about getting a hail damaged car? If you are planning on keeping it for ages anyway you may do ok. A chap at work is getting a new Honda Jazz for less than 16K (I think) I do know he is getting ~ 6K off the price. Depends on how long you were going to keep it etc. He has found 4 marks and is really impressed as he has trolley dints etc on his old one that are worse!
Happy shopping