I agree. I was questioning the lads in the workshop about it the other day and mentioned a router, but they dismissed it as no goer. They where running a bit of ply of the end of a T piece as sospan mentioned above, but it was only for small arcs to create a circle of probably 1m dis or so, and it wasn't that successful in regards to accuracy. As you said its a time and motion thing. Even with a router, I am guessing you would have to fit the ply on to the end of a trammel type T square set up... Cut your outside radius Move the trammel T square set up back to cut your inside radius. Move your ply up and your trammel back to the outside radius and repeat. The whole idea of this exercise is to cut multiple sheets at the same time, a jigsaw just doesn't meet the grade with regards to blade deflection and concentrating on the line drawn by a template
Something like this maybe, but the ply would be fed long edge first. And the whole thing would have to be sat on some sort of roller bench set up ?????? mmmmm
Why not make a jig that leaves the ply in place and moves a decent jig saw or router?. mount the tool on an arm with an adjustable pivot. wouldn't be too difficult to make up sliders and arms in ply mdf so you put the sheet you want to cut in place and then position the pivot and radius to make the cuts. I'd favour a router, and don't see why a decent powerful router would be inaccurate. I've cut circles out of (single sheet 18mm) ply for garden table tops by mounting my router on a ply arm pinned through the centre on a pivot with no problem at all. You will need a few passes.
You might have to get the original profile made up by a producer of such, or set of them on the basis of what you know works for you. ie arcs that make up circles of standard sizes. The profile would need to accept the usual router bearer of 30mm or so. Out of that create your top section for the router to sit on. below that a tray where the ply slides though and gets cut. Okay for occasional usage but if the business expands you would have to go cnc production.
If you have a look at the Fetool Carvex, it is similar to the Maffel with zero deflection over larger cuts. About 13mins into the video he cuts 100x168 maple plank and 100mm one absolutly square