I was looking at a zipper foot to get close to the edge. The width of the foot seems like it would make it difficult to sew small seams. (I was hoping to make some backpacks and the like out of Cordura.)
The mounting of the feet to the machine seems to be oddball because the outside foot attaches to a round post, not a flat bar. I've found a couple on the internet, but they seem to cost triple what the "normal" industrial feet cost.
If you could post picture of cording foot zipper sewing, it would help.