yes, i did the tracks in blender. this works great. you create a mesh tile and then use the curve and array modifiers to clone the mesh tile along a curve. the curve stays editable. i used separate segments for the asphalt road, the gravel road, the bridges and so on and at the end i modeled some connection pieces.

by the way, i originally did the tracks for the http://supertuxkart.sourceforge.net/ project a few months ago. i wanted to test the blender workflow for creating race tracks and taking part in open source projects is kind of fun. they reach a huge audience with being part of linux repositories and distributions.