What do you guys think about ABS panels for package tray and door panels?

My package tray is all kinds of disintegrated and dead...yes, leaking rear window. As soon as the car is driveable again the first thing on my list is to get it to stop leaking! Seals and weatherstripping are already on the way, but that still leaves me package tray less. I was already thinking of doing the door panels in ABS plastic because I am not a fan of cardboard, but then it occurred to me that I might also be able to use some paneling for the package tray.

ABS would not be affected by any leaks that I may encounter in the future, it is flexible if I don't get it too thick so that I can still pop it in there, and comes textured so gluing some fabric over it would be a piece of cake.

Do I just sound crazy? eplastics.com is down in San Diego and I can go pick it up from them there...yes, it'll cost a couple bucks more than cardboard, but I think it might have more longevity to it. What do you guys think?