Roulette and Bob Barker solved this problem long ago (analogously to LSL’s crosssection approach above). As the manufacturing is stressed you just make the things bigger :).
My personal preference would be to glue a n-sided teepee onto a hemisphere or cone and spin the thing.
You could use this with the free-spinning-inner-wheel. Have an inner sphere weighted at the bottom, with a spot on top, and a semi-transparent outer sphere divided into regions. The result is the region the spot lands in.