I believe we're seeing migration back to 30" here in NE IL. I know of a couple of neighbors that have gone from 15" back to 30". I do not know of any neighbors that have added new narrow row bean equipment, unless it was in conjunction w/a wheat planter. Another poster referred to Beck's data. I believe they show only a very small yield gain of 15" over 30". I personally question "small" yield gains on accuracy. Especially beans.

I'm not sure we see the big yields in beans in NE IL that others talk about here. So, maybe we're not giving up that much to begin with. I believe implement dealers also report decreased narrow (=less than 30") bean rows. I remember when it was a big deal going from 38" row beans to 30". When planting 38" row beans we used to shove the markers in on our 494 planter to gain a little extra. But, that was probably more for combining reasons.

Again, row width is probably a "here" thing.

Re. seeding rate...it seems that just about all publications & group discussions indicate that lowering seeding rates should be on everyone's list of "things to question...". U of IL indicates that they see no difference in yield vs seeding rate:

http://www.ipm.uiuc.edu/bulletin/article.php?id=930

They do mention that SW MO guy, Cullers, grew 150 bu beans using 300,000 ppa. If one is shooting for that yield, maybe you'd better keep the population up there.