Something to consider that those Square Foot books totally ignores... if you live in an area where you receive minimal rainfall in the peak heat of summer, consider lowering your bed below the ground level. I do this for my onions and peppers. If I water a raised bed, the water seeps to the grasses growing around the beds and encourages weeds.I was looking at Square Foot Gardening, then didn't actually try it.
Growing corn and pole beans together is pure brilliance, and rather handsome to boot.
By digging out a bed below ground level and using planks to separate the beds from ground level, and then filling with soil to just a few inches below ground level, you get better use of the water, and it doesn't encourage weeds.
also, some plants do not like crowding roots. I have found the advice in those books almost pointless at times. If you crowd most vegetables, they produce really small fruit, if not shut down fruit production all together.
All in all, it is a good concept. Just be careful about crowing. And, consider lowering a few beds if you live in areas with droughts in peek summer.