Tried using the silicone caulking idea I had.. works fantastic, though application can be tricky.
Silicone caulking as an alternative to latex works find for durability and flex, and also is good for people with latex alergy, however due to it comming in a paste/gel form it's not as easy to just spray or paint on. you can thin silicone out with water in a cup to make it paintable, but this has the effect of making it set MUCH faster (it will start to self cure within 5-10 minutes instead of in an hour. the DAP brand silicone I tested with came in aluminum gray, and was a moderatly fluid paste that i spread on to the foam easily. on open cell foam it soams nicely into the surface a bit and will not peel off, however with dense closed cell it tends to peel away from the surface unless you rough the surface up a bit first (quick scrub with coarse sandpaper did the trick nicely on the pool noodle, the camp mat, and the fun foam sheet, had no problems with common pipe foam)
Common colors for the silicone that I saw were black, light gray, dark gray, aluminum/silver, white, beige, and brown. Silicone can be tinted with added pigment, but you MUST tint/color the silicone and then apply it, because silicone is nearly impervious to everything once it cures. Also as a note, Silicone and Latex are incompatable. Chemicly speaking, latex and silicone will never bond to each other, so this can be used on purpose to create different effects. A mold made of silicone will easily release a latex casting and vice versa. and it is common enough to simply use household latex paint to seal a mold before latex casting to get an easy smooth surface with a clean release.
