With a planet explorer type game in mind, as part of a space-theme, I started playing with the radial gforce. Nothing special in this project, except that the planet is optimized as low as I could for a 1500m radius. That's almost 10,000m around the equator.. With a poly count of only 9800. I'll need to double the poly count to get rid of the "bumps" when you drive, but it is indeed viable for a game.
I will need to figure out how to apply a tiled texture to the mesh, in order to get detailed terrain across the globe, before I start shaping the hills and valleys.