We had a couple of guys "experiment" with buckwheat as a cover crop last year after wheat.  Corn no-tilled into it this spring went really well.  Not a lot of residue left at planting (kind of like soybeans) but ground was nice and mellow. I've read that buckwheat mines calcium. One interesting thing, two farmers planted some with clover.  More specifically they had a little clover left in the drill at buckwheat planting and that clover was a lot better than any straight clover.  The SWCD bought a bunch of buckwheat to have farmers mix with clover this year to see how it goes.  Buckwheat isn't expensive, it grows quick and will die with one cold stare from my wife!

SRI - Love your description of no-till...not sure I agree, but it made me laugh none the less!!