I picked up an InFocus 4805 at Costco (a bit more than 1 AMU)
and it came with a 6 ft. screen "window shade" type. Mounted it on
the ceiling, works fine.

My friends went with the screen material (there are a number
of suppliers, check google) and created frame to mount the material,
then mounted that on a wall. This definitely eliminated any
ripple or waves. On the other hand, I haven't noticed any on
my window shade version, either.