Don't let the surf purists spoil your fun. Kiting in the surf is more than just bottom turns and smacking the lip on a surf board.
On a twintip you can enjoy the 3D terrain park just as much, riding down the line of small waves a conventional surfer wouldn't even bother with, outrunning the odd big wave or using it to boost, followed by a slow rotation and landing back on the same wave. Then there's the speed runs along the troughs, where the waves block the chop making the water surface smoother than a non-surf beach in similar wind. And the friendly waves push your board where it needs to be if you happen to drop it.
Did I mention in SA we've got hundreds of km of 4WD accessible surf beaches that are perfect for downwinders?
I've been thinking about the ideal TT for waves. So if you want to ride waves well then the more rounded shaped boards will do that. However they will give you less pop and be worse upwind.
So.... I'f your primary goal is boosting off the wave lips then the rounded profile is not for you. You need to look for a more rectangular shape. Also the lighter wind you go out in will also require more tip volume.
So for a booster in the waves, go the rectangle shape. But to make it quite wave friendly look for a board with high rocker. That will smooth the chop and make the wave performance better while still having good a goo load and pop rail for boostage.
i definitely agree with not letting the surf purists ruin it for you. i have typically ridden only surfboards for the last 6 years but in the last couple months my boards have been getting shorter and shorter because i wanna try some different moves in the waves that surfboards just don't allow you to do well. this is my latest little project. only 127cm long 
all the boards i make are reshaped out of old surfboards that have snapped noses/tails and/or delam and this board came in particularly messed up so i had no choice but to cut it down shorter than average. still unsure what the end result will be. the board still has lots of work to do but hopefully i'll get it done before the next solid breeze.
it has quite a lot of rocker. the fin setup (may change) will be two larger fins on the outside tail and three smaller fins, one in the center and two at the nose. footpads, it will definitely be setup mutant style for better snaps on the wave. also i am adding balsa wood inserts to the fin areas for extra strength.
not sure if this helps with ideas but just give it a go at making your own. like plummet said, there is no better feeling than riding a great board you have shaped yourself.
Wave purists or fashion victims. Those Franz boards are most awesome and I like a bit of experimentation - no reason a kiteboard needs to be like a surfboard that is designed to be paddled lying down, although it is awesome for carrying around less crap if one does both..
