What frameless are you talking about? I am pretty sure any of the North Fork Outdoors frameless and even the Outcast frameless offer everything a framed boat can offer. They are crazy light so maneuverability and speed are off the charts. Structural integrity, with the aluminum motor mount you can run up to a 9 hp gas motor on any of the NFO frameless. There are at least three air chambers. The seat area is not touching the water and the rocker end give it a very small foot print. They are very safe and easier to climb back in should you fall out.
Need to check one out some time, you would like it I think.
But I am interested in what you come up with frame wise. My aluminum frames are light and nice but I would love to try a synthetic...LOL