Replacing Pella internal pleated shades

OK, these windows were purchased/installed in the early 90's. The pleated shades are all drying out and the fabric is cracking at the folds. All the mechansims work fine, and getting to the shade is not a problem. We need a source for the pleated shade material so we can "rebuild" the shade using the existing mechanism. Pella discontinued this line, so they don't offer replacement parts.

Any source would have to pre-punch the shade with the correct hole pattern which might even be somewhat generic. The shades are about 24" wide by about 48" high (extended).

Any/all help is appreciated.