Buy sheets, rip the strips on the table saw, and use a router table to machine a radiused bull-nose on one edge and matching relief in the other side. This way they will pivot inside each other to reduce the amount of fairing you need to do and will increase the glued surface area.
How squishy is the foam? I'm just thinking about ways to do it, and if you set it up in a shaper you could have a powerfeed and keep things consistent for width and finish of the cut.
