In search of a "Road" System

HI!

I am in search of a road system.

A system that will take like let's say a doodad unit or other non-building unit, create a road, and change the faces of the road to match other roads around it (and change their faces too).

Something that will have a + roads a L road a T road and a I road.

IF no one knows of a road system (I searched and could not find), then what is the best way to go about it? I was thinking of creating doodad units and change their exposed face depending on other roads surrounding them. I would use a "dummy building" to trigger the creation of the doodad, then I'd delete the dummy and keep the doodad. Or should it be a UNIT with Locust? (road needs to be invulnerable, unselectable).

Just cruious.

ty ^_^