Very easy, but very expensive. The material is extremily technologically complex. I've just installed one at my parents house. Screen Research 2.4m across, inset into the ceiling and electric. �4k roughly. Stewart Filmscreen are even more. Easily available, but not the norm because of the price. Screen Research is US and was built to order and imported by the UK rep.

I couldn't find the same product type available for less money. Only the top-end firms do accoustically transparent electric screens. But maybe, for a fixed screen you could spend a lot less. You just need to build a frame, buy the material and tension and align it. Not as easy as that makes it sound!

Office: Meridian 500.1, 568.2mm, 557, 505, Dali Helicon 800 L/R and C200 Mk2 Centre, BK Monolith FF cool
Cinema: Valerion Visionmaster Pro 2, Arcam AVR31, KEF LS50 Meta LR, T300c, Focal Dome On-Walls, PMC Twenty.Sub
Bedrooms: Meridian 2x M80