Scorchie is right.... If you're going to get a custom shape have it thinned out, make it a little wider and shorter. This will allow for good float and you can still jam turns with it. Keep the rocker to a minimum it you go that way. Put some bigger fins, like G7's and those fins will give you more drive.
There are actually some free autocads for surfboards on the web if you want to tinker around with designing one yourself.
Check this out.... at the very least its fun to play around with!