Degausser on 23 December 2011
In terms of manufacturing hardware i think they might be. Maybe there was a short period where Nintendo were making both Gamecubes and Wii's (On top of DS & GBA) but I'm not sure. Just cause a system still have software released doesn't mean it's still being manufactured.
SEGA might have but again I'd assume the 4 listed weren't still in production at the same time.
