So here's what I ended up with:
Lime green rocky mountain storm with a home brew speed rail frame. Frame is 56x48. Installing 8 inch towers. I still need to put the dowels in the frame connections, but its getting there. I will weigh the frame, but it doesn't seem excessively heavy. All in, the frame with towers cost me 260 bucks.
I love it. There's enough space even with cooler up front that I won't be hitting the passengers with the oar handles, and its light and narrow enough that I can shuttle it without a trailer.
Super stoked to get it on the water this weekend.