I plan to purchase the 5DmkII as soon as its in stock at B&H. I've got the cash for that. My plan is to sell my current 5D w/grip for $1100 (reasonable?) and pick up a 50D as a backup. I'm looking at it like this - the 50D will be brand new, not 3+ years old like my 5D. Its a crop sensor, so I can use it with the 70-200 and 1.4 extender to get 400mm+ range for those times when I need it. Also, the 15mp files will be easier to upsize for Getty (to 17.5mp) than the current 5D.
Am I missing anything? Any reason not to go with the 50D? The 40D would have been an option, but the file size issue is important.
And then there's the option to use that 1K towards an 85mm f/1.2 That would be a pure luxury purchase, but the 50D sort of would be as well since I'd only use it very occasionally.