Any pipe within a pipe stoves?

Are there any manufacturers that use a single pipe for intake/exhaust? Or can this not be done with pellet stoves? Do any gas stove manufacturers do this?

Thanks.

Selkirk makes a product called Direct-Temp for pellet and corn stoves, basically a pipe within a pipe. The fresh air is draw in the outer edge between and two pipes, the exhaust goes out the center pipe. This is what I used for my install, I like it because there's only one hole through the wall to the outside and the larger diameter pipe looks more like a true wood stove vent. Although not the Selkirk website, here's a link with info from a stove shop I found online: http://www.northweststoves.ca/chimneys-venting/selkirk-direct-temp.html

Selkirk is the only one I know of that is doing this right now. Bixby does but their pipe is proprietary.

I think Simpson dura Vent also has the a wall thimble with exhaust and fresh air . Harman also has a wall thimble with the same holes.