http://www.canoegear.com/html/ check out the pontoons for a kayak. I don't stand in mine, but installing a set of these for the same reason stabilty when standing and moving around the yak.

They say 35" from the rear of the back seat and I am getting a new hatch put in in the rear to accomadate the bases for the bar. Its a neat system and you can put the same unit on your canoe.

Hobie Quest Fisherman is the yak I have and Hobie does a great job of backing up the product. I recieved a new yak for a small defect in the one I had. The reps work well together so getting it replaced 1200 miles away was possible.

Have a good one

Philip