I have owned one of Rob Davidson's Sky Dragons with a scale release, and desert ironwood scales in BG-42 steel for almost 2 years.He has had it twice in that time for vertical play, and the last time replaced the blade without cost. He has a good warranty as far as that goes.
He also had a good write up in Tactical Knives in March of 2001 I believe(would have to chase it down in my mag collection). Anyway the one they did a write up on was the Sky Dragon also, and the writer noticed the same problem of vertical play.
The vertical seems to get to a certain point, and goes no farther but just enough to be bothersome if you are as particular as I(also to the writer of the article in the mag because the one he was testing also had vertical play).
Other than that he does beautiful work, and his knives are heat treated a little on the high side, and takes a bit of sharpening to get a good edge but when you get there it holds it well.
I paid $400 for the one I got, and don't carry it much as I am just too much a fanatic of vertical play, and feel if you spend this much on a custom knife it should not have it. I just decided to live it rather than send back to him again, and just keep it in my collection. Like I said someone else might not be such a fanatic, and would not consider it a problem.
He is a really a nice person to talk to, and deal with, and I just don't want to become a pest, and this is just my own opinion.......
Larry
Larry