Exactly right guys. When I have just a scattering of leaves, I simply run over them with the walk-behind mower and the shredded leaves stay behind. However, around now in Fall, the leaves pile up so much that simply shredding them with the walk-behind mower and leaving them is a dense enough spreading of leaf mulch that it does indeed kill the grass. About the only blessing is that at least they are easier to blow after I've shredded them...but all considered, it's a lot of work, and I can't think of much that I detest more than clearing wet leaves!
I have used my neighbor's walk-behind leaf vac once. It worked well, but I had to stop every 10 mins to empty the bag.
Ya know, I'm actually a little surprised that no mfg already makes a riding mower with leaf vac/shredder/bagger deal already built-in. I guess the Snapper Hi-Vac is about the closest to that.
Dave