Old thread I know, but I was in the same position and decided to design one I could 3D print. Not as strong as steel, but a lot easier and cheaper to replace if you have a 3D printer.
https://www.thingiverse.com/thing:6948609
I know this is an old thread, but I bought one of these track saws and was disappointed. Mainly because of the 4 small tracks that need to be ganged together to make 100”. On top of the difficulty in making them straight, they are only connected by one linking bar so they are very floppy. And...
I installed one of the auto drain HF kits years ago. Last year I began wondering if it was doing its job and remove the drain plug, and not a drop of water cane out.