We just replaced the channels on Conundrum. Integrity Marine Corp, part #1035. The rep there told us that they used to supply Waterline/J/Boats
. We ended up cutting a couple inches off to fit and we also profiled the one end to match the original.
I will say that they were quite expensive. You need to buy four channels to meet the order minimum. It ended up costing $170 for the four, with shipping from Integrity. I think the aluminum extrusion from Home Depot would be much cheaper. But the white channels look great on the boat
So we have a pair of channels left. Let me know if you'd be interested in them. It will save you from having to buy four!