"I can achieve more if I do a "two-hand" single stitch-- i.e., all the way down with the right hand, pull it through on the bottom with the left hand, then do an "up" stitch from the bottom with the left hand, pulling all the way up with the right hand. BUT this takes FOREVER. And frankly, I think my stitches are less consistent and a bit messier."
There is a gal in Texas (don't remember where) who does beautiful hand quilting one stab stitch at a time. She said in the article I read that she is actually pretty fast at it.