@Erica thanks for the comprehensive answer.
Erica Wisner wrote:Separate stoves gives you more control, and also allows you to fire up only what's needed
I think you are right. When I think about the way we use our wood stove we almost always have the lids down on the hotplates when using the oven. It would be complicated to build that kind of feature into a cob stove/oven I think.
Erica Wisner wrote:Here's our massive double-chamber cob oven, burns a little cleaner than the varieties without a smoke chamber / chimney
I've seen it in one of Paul's videos and it's impressive. I just got the plans

I think this is the correct link though for anyone reading this in the future:
http://www.scubbly.com/item/75815/?affid=8105