There was a thread up somewhere on wakeworld about building something that looks like a balance board but helps you with handle passing. I can't find it and am looking for some help!
Well, at West Coast Camps, Mike Schweene has one. It is pretty cool. It is weighted on the other end to give you a better feel for handle passes. I will see if I can talk to him and ask him what all he used to make it.
Basically you use two pieces of plywood and make a huge Lazy susan. It's pretty easy. Then you attach a handle with weight through a pulley to simulate the pull of the boat. They are nice, just be careful to keep them away from glass doors. A friend chalked her back up and got stitches from bailing through it. No bueno!