looking for a new ski

The previous post by Inliner reminder me that I am considering a new ski for my father. He is one of the smoothest skiiers that I have seen and stills enjoys getting out there. However he knee does give him a bad time if he overdoes it.
My ski is a little short for him and now that he skis a little slower, this is more of a handicap. I bought him a Mid SX last season but he finds it "slaps the water" when he crosses the wake and that shocks his knee.
I am a little confused by the current line up of skis. They seem to promise that each ski will do all things for all people.

What I am looking for is a good intermediate ski for someone who it 6' 1" and 185lbs. He prefers just skiing for fun (no buoys anymore). He also prefers long smooth carves so "snapping" turns is less important. At the moment I am pulling him at about 26-27 mph.

All advice is welcome.

I am currently using a Connely F3 Concept. I have found that it holds the turns very well. I am not a very good skier and I tend to ride flat across the wake sometimes, I have not had a problem with the slap either when I am edging or riding flat. I usually ride at either 28 or 30 mph and I'm 165 lbs. The O'brien ski's I've tried in the past seem to give me the slap your talking about.

Check out the HO Rival series. While it gets squirrelly at excess of 32mph it's great for getting up, rough water and smooth turns. Even behind a V-drive it crosses the wake very smoothly.