I wonder if you could use the construction techniques that they use to build miniature golf courses to build a racetrack from concrete and CRC carpet. Wait! That doesnt sound right because now everyone is imagining trying to race their car between the blades of the windmill.
No what I mean is Concrete lanes with any elevation change you want including a banked curve, off camber corner, corkskrew, anything. Then have CRC carpet glued on top instead of the grass carpet. No mermaids. No Clowns. No windmills.

If I could have it my way I would have a medium sized asphalt track with the straight on the front side, into a banked sweeper, into an off camber 180. Put a Corkscrew on the backside and a tight technical infield and you would have a classic permanent track. Sigh. I will just keep dreaming for now.

Oh yeah on the backside I would have an 80's style 1/10 offroad for racing Scorpions and Tamiya Cars.