Canon sells "refurbished" cameras at a considerable discount. You can see the 5D MKII on this page:
Canon Direct Store- EOS 5D Mark II (Body) Refurbished
Contrary to what you might think "refurbished" is basically limited to cameras that were either purchased and returned for
non-repair reasons or the box was opened in a store and the customer decided against buying. In either case, once the box is opened the camera can't be sold as "new" so Canon sells them as "refurbished". According to Canon they are not cameras that were sent in for errors or repairs. They are thoroughly checked out and you are basically buying a new camera for a really good discount.
The only downside I'm aware of is the warranty is for 90 days instead of a full year. However, as somebody pointed out, some credit card companies extend the manufacturer's normal warranty by a full year or two. So, if you purchase with one of these cards you are basically getting a full warranty on the camera.
I purchased a refurbished 7D and a 5D Mk II and both cameras are working perfectly. The camera comes in a box with all cables, manuals, CD's etc. that you would get with a new one. Unfortunately, at the moment the 5D MKII is out of stock. You could bookmark the page and keep checking back. You can also call them. I think the number is 1-866-261-9362. Be sure to ask for the refurbished camera department.
Finally, there are a lot of rumors about a 5D MK III. So far it's just rumors. A major camera and imaging exhibition, CP+, is taking place this week and there could be further announcements. It could be worth waiting a few more days to see if a newer model comes out. Hope this helps.