I'm not sure keeping a large stock of refurb 7800s 'just in case' makes much sense on the books. That'll translate to a pretty significant unsold inventory line item. Investors don't like inventory that lingers around on the books very much. It's easier to provide a replacement card from a new series than to keep a warehouse full of rapidly depreciating old hardware.
Experience with pulling off just in time supply chain management has pretty much convinced everyone that keeping warehouses full of stuff on hand is a lose.
So, I guess I answered my own questions. Refurbs galore. The only question is from where, and for how much.