make normal maps during runtime?

Hi, I want to procedurally generate geometry like buildings or stones. to make it look good, the idea is to, say, make a high poly stone and then generate a normal/ diffuse map for the stone. Is it possible to do this during run-time in unity? until now, I only procedurally generated geometry in maya using python where i could later generate normalMaps using mentalRay. But this limits me to pre-generating things and then shipping a number of pre-generated assets with the game.

What I now want to do, however, is generating geometry directly in the game.

Any Ideas how to approach this?