I think Murt's wheelie truck is still alive and well (with Murt's son at the helm).
When it was Skytrain, it was road legal. Murt gave me a lift from Leeds to York and it certainly caused a few stares along the M62!!
At the track I also had the experience of riding shotgun when it was hoisted into the air - with a slightly surreal view through the windscreen, blacktop - blue sky - blacktop and surprisingly little impact on return to earth!
Re: the Marina wheelie car - I don't recall seeing this vehicle at York before I left for fereign shores in '83 but whether it appeared after then I don't know.