I have an excellent condition ATI 3870 video card Mac & PC edition. It has 512mb of Vram.
More info here :
ATI Radeon™ HD 3870 Mac & PC Edition - Overview
This is designed to work with the 2006 & 2008 Mac Pro. I'm not sure if it will work in a 2009 Mac Pro.
Located in Etobicoke @...