I started building wide thick surfboards for river surfing, in Colorado. I ended up taking my 6’4" x 25"x 3 1/2" to cali and the board ripped. It paddle as fast as a 7’6" nsp funboard and at 155lbs I could even duck dive it in head high surf. the board had a bit to much curve thou so it was a tad slow outside the pocket. building another one at 24" wide it should be a bit quicker. The only problems I have with wide boards is the wide tail anything over 10" and it feels like a cork to me.
I have also been building extra wide wakesurfs for the heavy weights, and those who dont want to weight down their boats.
[img_assist|nid=1058753|title=6’4" riverboard|desc=|link=none|align=left|width=480|height=640]
[img_assist|nid=1058726|title=heres a 6’7"x24"X 3 1/2" I built for a guy|desc=|link=none|align=left|width=480|height=640]