Possibly used in those Walker prototypes?
And AmigaForever supposedly has a mode you can play with supporting this stuff.
I don't know how well it works though.
And I doubt it would be an improvement over a Voodoo3.
No, the AAA silicon was only part functional and was being worked up by Dave Haynie and some other Commodore engineers just before the bankruptcy, but was canceled so that attention could be focused on the Hombre Chipset, which was not Amiga Compatible but vastly superior to AAA. Had any of the commodore R&D been restarted, it would have been Hombre, not AAA that would have been developed.
Walker was basically an 030 based A1200 with some modern expansion busses like PCI and newer IDE etc...
-edit- a nice link to Hombre Chipset:
http://en.wikipedia.org/wiki/Amiga_Hombre_chipset as you can see it goes in a different direction to the Amiga and AAA, and is basically like a modern gfx chip.