You could always just take a spare rifle barrel, and/or bit of wire of the appropriate diameter, and have it sticking out of a bit of brush on "clump foliage" glued to a base, since a good sniper who is prone really shouldn't be seen anyway.
Another option would be to do the same from under a tarp, piece of corrugated metal, broken down building wall, etc., etc. too, if in a more urban environment.
Snipers aren't supposed to be seen.