Not so long as I thought. Brief details (and your drawing on a mid-grey background) in Spielberger's Waffensystem Leopard 1 and 2. There is a small artist's impression in which the road wheels are fully visible, no return rollers. Looks a bit like a T-54 with very long gun.
Very much a joint effort. Porsche for overall design; Daimler-Benz MB837A 8-cyl diesel; Zahnradfabrik AG of Friedrichshafen for track etc; Ruhrstahl for turret and gun. Production in India by TATA was intended. Indian optics, sights.
Intended to meet an Indian need for a 36-39 ton tank, the German submission would probably have been around 40 tons. Power to weight 16.7 hp/ton so around 670 hp; top speed 50km/h, 90mm gun. Armour 90mm, up to 130mm turret face, cast steel.
I've a larger artist's impression somewhere, probably as a photocopy, but I don't think I can do better than this. The project fell through, with nothing built. The Indians eventually went for the Vickers MBT, production beginning in 1964.
Anyone have more info/pictures of it? Sounds pretty interesting.