I found that the Pilots Shop at YPFL used to sell sunshield in bulk off a large roll (about 5' wide) but am not aware if they still do.
It is apparently the same stuff as the commercially available custom made items. Just buy a few metres of the stuff and cut them to shape yourself. I made a set for my car a few years ago and had them trimmed with the same cloth edging by an upholsterer.