Hey Jesse,
Not to drop a shameless plug here :elkgrin:, but this is the AT tongue bracket I'm selling because the receiver tube is too short for use with my military trailer (fixed length with the Max Coupler). I have another on the way...should arrive this week.
This bracket is designed for your standard 50-degree A-frame angles, and you could use a couple different receiver tube lengths for the flexibility you're looking for with general utility & towing longer kayaks. If it's something that would work for you, I actually have an old (homemade) hitch-mounted bike rack that I don't need, and could throw in. It has a ~3.5' section of 2.5" square (0.25 thick) that you could use for your receiver extension. Just an idea...
You know where to find me if it's something that would work for you.
Craig
AT tongue bracket & receiver:
You could use an extension tongue piece & coupler similar to this (posted above):
