I have a project planned to build a USMC assault-gun/ATGW vehicle based on an S-Tank fitted with a modified 152mm Shillelagh system. Because of the auto-loader, the gun would used fixed cartridge cases, thereby eliminating one of the original system's problems, while the missile would be modified to use the RBS-70's laser-beam-riding guidance system (a laser-beam-riding Shillelagh was tested for real in 1975). The vehicle would also have an M60A2 or A3 commander's cupola (havn't decided which yet)with it's under-armour .50 cal for all-round local defence.
The model would be presented in the type's "final fling" configuration, outside Fallujah in 2006, with AAV-7A1-style EAAK applique armour on the sides, blazer on the front, and modified stowage.
I'm also considering a USMC "Super-Duper Cobra" to go with it. This would be an AH-1W with the AH-1G flat-panel canopy, 30mm M-230 cannon from the Apache and air-launched Shillelaghs instead of Hellfires (an air-launched Shillelagh was tested for real too).