I don't have the room or need for a permanent outfeed solution for my tablesaw. I need to frequently access the rear floorspace of my saw for storage and space reasons.
I do, however, need outfeed support on occasion. I found a good solution that may be appropriate for people in my situation:
Outfeed runners. I put a rabbeted rail on the back rail of the table saw. I then just made a bunch of runners from scrap and added cleats to fit into the rabbet on the saw.
The runners can be positioned around the miter slot and can be moved as narrow or wide as necessary. You really only need 4: 2 for each side of the blade. Best of all, they can be lifted out, nested, and stored when not needed.
I used 2x4's for POC, but I will make them out of plywood for permanent use; any twist causes the cleat corner to lift out of the rabbet, and impede the travel of the cut piece.
The runners are easily repurposed as straight edge cut guides, bench hooks, etc.
Of course, this only works if you have a bench or some kind of support positioned appropriately.