In addition to the plastic sheets, which are not available at my HD here on the east coast, I have an alternative:
I just located some formica at Home Depot that I will try out as a screen for my LT150. It is WilsonArt White 1570-60 (60 is the matte finish which I will further take down with a 240 grit wet/dry DA [dual action] sander).
A 60" x 96" size is $1.75 a sq. ft. (may differ on location due to shipment costs) for a total of about $70. I think they go 72" wide as well.
The 1570 white is a "cool" off-white, between a light grey and white. It appears lt. grey next to the Designer White shade.
I like formica, have worked with it before, will mount it to an MDF substrate and 1x2 bracing frame.
Any thoughts prior to me ordering it?