Update - we have lift-off!

Kate is walking. It started last Friday, the day before we went to Lewisburg for a 4th of July party. She was just doing that hovering thing and occasionally taking one step, followed by a swift descent (i.e., plop, on her bottom). Suddenly she just decided to go for it, and next thing we knew she was doing 10-15 steps through the living room. She's not terribly stable yet, but she has the basics down pat. She still drops down to crawl when she needs some speed, though.