I bought one of these Surco 502L ladders to use for a different project.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
It comes with two pairs of middle supports that do not have mounting holes drilled in the ladder yet, so you can drill them yourself to match the locations of your original mounts. It comes in three pieces so there are options if you need to saw it shorter or otherwise modify it. I cut half the top loops off mine so I could mount it to the face of my trailer. The ladder uprights are 11 inches center to center where you would bolt through them, so measure your old one. It's 12 inches from the outside edge of the left upright to the outside edge of the right, with 1 inch aluminum tubes. Looking at a picture of a Northern Lite 10.2 I think you could make it work.