Blending multiple textures/materials on one mesh

Hey folks!

Since Unity iPhone/etc obviously don’t support high-poly terrains, we’ve created our own low-poly terrain meshes that snap together using a nifty grid system.
My question is, how can I blend multiple materials onto one mesh? Our artist is talking about vertex-paint shaders but I have no skills in this area.

Any help would be greatly appreciated, we’re willing to pay as well.
We’re talking about 3 materials with normal maps (sand, rock and grass), perhaps more in the future.

This way, we don’t have to create a UV-texture for every single mesh and save on memory.

Cheers!

TornadoTwins

Nevermind! Just found this:

-TT