Rickshaw: Thanks for the
aide-mémoire -- 10.0cm PAW 1000 was the one I was thinking of.
You know, somewhere at some point in time, I swear I remember reading a proposal from Giat (or Nexter) that involved equipping the Leo 1 with various turrets from the AMX 30 family... but the reason for swapping the turret from the gun tank went over my head a bit ...
That's been proposed a couple of times. One non-Giat proposal was Santa Bárbara Sistemas'
Proyecto LEOX. A hull was procured from Krauss-Maffei (and is still in Seville, apparently) but I'm not sure if the turret swap was ever completed. The point of the project was to eliminate drivetrain problems with the AMX-30E while avoiding British export bans on the Leopard 1A3's RO L7A3 main guns.
IIRC,
Proyecto LEOX was meant as an fill-in after the collapse of the 1985 domestic
Lince tank project (also by Krauss-Maffei and Santa Bárbara). There were a host of alternative proposals all involving new transmissions (or engines) for the AMX-30E. Eventually, Spain chose the AMX-30EM1 / AMX-30EM2 upgrades before moving on to Leopard 2E and Centauro replacements.