You could build one yourself with sections of pipe cut to your dimensions. NRS sells frames (bigger boats normally) but they also will sell you custom cut portions of their "unbendable pipe" and lowpro connectors. Outcast boats will also likely sell you a frame without tubes if you contact them. What company makes your boat? Perhaps contacting them will lead to another frame too. You can also post a WTB (want to buy) a pontoon frame here in the classifieds. There are a lot of folks here, maybe someone has a frame sitting around collecting dust that they will move in your direction. Welcome and good luck.