From what I read/see... a lot of assumptions in your numbers there... a LOT of assumptions...

You know what they say..... Liars figure, and figures lie....

Having said that... I have read that some guys are playing around with 60" corn. From what I have read, they are trying to get that earlier fall growth with a forage crop interseeded between the 60" rows. The idea being... allowing that sunlight to penetrate down into the canopy and allow that interseeded forage to grow.

So, here is my concern:  conventional herbicides (as in conventional 30" corn) are not designed to last all season.  These herbicides are designed to get to the point of canopy closure, and allow the closed canopy to provide weed control/suppression late in the season.  So, if you go to a 60" row configuration, are you going to have a lot more weed pressure at the end of the season?  When we have years where it is dry early, and then get rains late, it seems those late rains bring on a flush of late weeds. I would expect if you go to a 60" row configuration, that late flush of weeds is going to be exaggerated.   That is what I would expect.

If you are going to plant 100 acres of 60" row corn, why not plant 50 acres of 30" row corn, and plant the other 50 acres into a forage crop, and manage the two accordingly.???

There may be a place where 60" row corn is a fit.  However, as you may presume, I am skeptical of the idea as a whole.