A couple of the boats I like that I have found include the Alumacraft MV1648 NCS and Alumacraft MV1546DD AW. Both weigh 320 lb and have an open floorplan. The 1648 is riveted, made of 0.070" AL, and has a hp rating of 35 hp and capacity rating of 4 people or 1,000 lb. The 1546 is all welded, has a drop deck, has the option of rear split seat or rear deck, is made of 0.080" AL, and has a hp rating of 25 hp and capacity rating of 3 people or 720 lb. I'm not sure a 9.9 hp, or even a tuned 9.9 with a 15 hp carb, would do the trick on either though.