Tom,
I've been considering something along those lines too. Just don't know if I want to see big pink sheets floating on the pond. It's right outside the front door. Maybe some kind of floating island tho.
I used 1 sheet to make a pair of 2x4 turtle/duck floats and covered them with green indoor/outdoor carpet as that's what I had on hand. Lot's of variations on that theme to hide them if they were to be permanent. I don't really need the additional shade though except around mid-day as I've got trees circling the pond.
I'll pull mine out of the water once it start to ice over but you probably don't have to deal with that issue so aesthetics may be more of an issue.
