I modded my sluice by putting in Gold Hog mats in place of the riffles/miners moss. I have a section for fast(er) waters that has Talon/Motherlode mats and another section after that with Wave mat and some odd and end mats. (I'll probably play with the mats) I have a 3rd body that I plan for a Wave/Dream Mat for fine stuff or slow(er) waters. I'll run 2 bodies depending on the conditions but I suppose I could have a 6 footer if I really wanted (and had enough water flow).
The moss is a pain in my opinion and I love the Gold Hog matting.
Maybe they could make a plain body with no riffles/moss slots or anything else-just the connectors to hook them together at the ends. That way I could modify them in all sorts of ways. They're inexpensive enough, light-weight and great modular design.