I plant corn in early July in zone 5, for fall harvest. I would think that you'd do even better in your zone. I've also planted beans late like that for a fall crop. I would think that since you've got the number of days to harvest putting you well before frost, you'll be fine. Things will grow slower with the shorter days of late summer, though, so add some days to harvest time for your second crops.

You've made a good choice between beans and corn, with a nitrogen fixer preceeding a heavy feeder, and vice versa. But you probably knew that already :)

I'm in North Carolina too (Triangle area) and I've had good luck with late plantings of beans. I have never had luck with corn because the cute little tree rates (also known as squirrels) always destroy them, so I can't give you any advice there.

The 65 days for the beans refers to when they start producing. They will continue to produce for some time. So I'm not sure you're going to be able to follow the beans with corn because it'll probably be too late in the season. Unless you rip the bean plants while they still have more to give.

-Anne