A lot of good yielding wheat in the past has been planted with the old Dempster grain drills on 14" spacing, although for different reasons than most on this forum face.  We try to get enough ridge to prevent blowing dirt from mowing/unearthing the young plants/seeds.  The old Dempsters had a 3 or 4" to 9" wide shoe and had a spreader at the bottom of the seed tube that spread the seed over a 2 - 2.5" wide area down the row.

I don't believe the varieties today will stool out adequately to take advantage of the wider rows and provide canopy.  In our area, moisture usually has more influence on yield that other variables.