Liner for Upper Cage

I am making some repairs to an older Dob for a friend of mine. The upper cage is line with aluminum flashing, which is pretty beat up and coming away from the inside of the rings.

I believe a lot of folks use Kydex here. I checked a few ATM suppliers and didn't find anyone selling it, so the first question is: Where do I get Kydex (need 10.5" x 48" minimum)?

The second question: Is there something better? I do want it lightweight, as the OTA is a bit front heavy now.

Clear skies, Alan

Buy ABS instead of Kydex. It is much cheaper, looks the same and is easy to cut with a box cutter or Exacto knife. Just scribe it and snap it off along the line.
It is available at plastics supply stores in .030-.040-.060" thickness. The .040 works best for this.
http://www.professionalplastics.com/cgi-bin/pp.pl?pgm=co_disp&func=displ&prrfnbr=85252&strfnbr=3&prname=ABS---Forming-Grade-GP
Here is one online sourse, but they have a minimum order. I order 3 sheets last time from them.