There is another thread all about this floating around here that we started yesterday, but bere you go, it is a homebrew version. I am getting better pics of the latch later today. Should have them posted by later tonight. Hope this helps. Its a rockstomper hinge and an industrial latch. Works great. Feel free to ask some questions.
More info on the hinge and latch, please. I've some ideas I've been wanting to play with for bumpers, and finding a good hinge for the tyre carrier just hasn't made it to my list yet (and, frankly, why reinvent the wheel?)