I'm wondering why you wouldn't want to have the corn width and the soybean width the same.  It would make it easier for rotating.

I remember reading about this concept years ago in one of the farm magazines - it might have been in The Furrow, but I can't say for sure.  I believe the idea came out of the droughts that occurred in the 80's.  Guys noticed that in standard large fields, that the corn seemed "okay" driving along the lane, but when they got into the middle of the field, they found it had not pollinated - there was too much heat accumulated in those big blocks.  So, someone came up with this idea of narrow alternating strips to allow better air flow thru the crop canopy. 

Never did heard much about the idea since.  Seems like the RR technology (and now the LL technology) would make it easier to adopt.