Being I don't want to waste your time or challenge your beliefs of thinking outside the box.

So here goes.

Ever notice how a "one legged" burn out left on the street is almost always perfectly straight?

Notice how few posi/locked rear burn outs are equally as straight?

Ever pushed sideways on the rear of a car while doing a low-speed burn out, and learn how easy it is to move the car sideways?

Ever hear how proud racers are of how straight their car leaves while accelerating and the effort they make to achieve that result?

My assumption here is it takes very little rear sideways grip and/or force to keep a car going straight under heavy acceleration.

Would not the simple addition of a free rolling lightly suspended non steerable fairly narrow rear middle mounted tire slightly behind the rear axle achieve the sought after directional stability so cherished?

Of course, likely is 100% illegal in sanctioned racing,

Maybe it could be deployable at speeds say under 30mph when throttle reaches 100% or wheel spin occurs?