While not a perfectly flat green I use BPB 17, a par 3, to practice on. Lots of rough, heavy rough, and bunkers surrounding the green to practice.
Like Alosso said, just whack it near the green off the tee into the rough or bunkers and use mulligans. Then when you want to try a different shot, hit the ball to a different location without using the mulligan and continue on without leaving the hole.
BTW, the mulligan feature is available with the single hole play: WGT Community, golf courses.