You guys probably know this, but with small inflatables like canoes/duckies, the problem is not load capacity but volume, due to the room taken up by the side tubes. Two guys, packs, and then you try to put a moose in the boat?

But if you have two of the SOAR, or two similar size inflatables, it's really easy to make a cataraft by lashing them together with a couple poles. Leave a space, lash together, put some small poles on for a platform between the SOAR, and *poof*, room for lots of stuff.
Rafting together also can get you through some big water, depending on paddler expertise. I did this with a couple duckies when a friend still wanted to go along on a Tatshenshini day trip, but her pregnancy was getting along and she didn't want to ride on a guest raft. Acts as a side x side R2, ran up to Grade IV no problem.
Versatile little inflatables. Have fun.