Well... three things factor in to this equation I think.
1) Level of experience of the photographer.
Also the most important. There are exceptions.. but someone who has not spent at least a year or two OBSESSING about their picture quality, and constantly trying to improve during that time, has no business even being a second shooter at a wedding. If there's one thing you don't want to F up, it's someone's wedding.
2) The equipment.
A full frame DSLR with a couple f/2.8 zooms and some faster primes, along with at least one powerful flash would be about what I'd consider the minimum if I were to shoot a wedding by myself. I'd be more comfortable with a backup body.. even a cheap one. Also, it's nice to have a lens with a different focal length already attached to a 2nd body.. this way you're ready if you need it.
3) Level of experience WITH the gear.
Right now I have a T2i... but it's taken me about a year to get comfortable with it. I would want to take at least a month or two to get comfortable with a new camera body before I decided to use it for something serious (like a paid shoot).
Anyway, tried to give a serious response in case you were actually being serious.