The Gorilla glass is in. 12 x 12 x .031 and it is very flexible if two opposite sides are supported. If all 4 sides are supported, it will still flex but not very much. Maybe .05 to .1 inch. With 2 sides supported it would flex an inch or more. I am trying to come up with a flexible seal for the unsupported sides. I tried some tygon fuel line but it is too stiff. If you pinch it, it feels soft but when you try to compress a foot of it there is too much resistance.
I think that either a foam weather strip with a layer of silicone or some type of thin strip that is bent into a "U" shape might work. Maybe cloth that is silicone impregnated.
I don't know if there will be any time for this over the next couple days or not but I thought that it might be good to stir the creative juices out there.
Discussed here are the various tilt/ slide and Z-Axis mechanisms