Looks a lot like the collection funnel in the bottom of my Craftsman 21833. And, if i recall correctly from looking at the manuals when i was shopping, the Ridgid R4512 uses something similar as well. Mounts between the "cabinet" and the leg assembly, porting through the bottom. Seems pretty functional.
I don't recall your saw Jerry, but on a contractor or hybrid seems that it would be as simple as cutting a sheet of aluminum to the dimensions of the leg assembly, then cutting an opening for the Big Gulp and riveting. Punch holes to mount the saw and you'd be in business.
I could also see suspending one just above and in my case slightly to the front of the blade--might capture some of the "whiskers" i get when ripping.