Not sure what your requirements are in regards to picture quality but a very easy, cheap albeit unsophisticated solution would be to get a reversing camera. In case you've never heard about that, it's basically a parking aid that consists of a camera and screen.
Something like: http://www.ebay.co.uk/itm/12-24V-IR-...MAAOSwM4xXZ0wK
I have no real experience with these though and I imagine that the quality is not going to impress anyone. It should however give you some idea of what's happening in front if you mount it on the hood instead of the boot.
The cats are watching us...