Well, I thought I'd be ever-so-clever and generate a sky cube from Artlantis, since it has parametric clouds for its sky. If it worked, then one camera set-up could generate any number of different skies by changing the cloud parameters.
I set up six cameras, each names with the names Eric gave, with 90 degree view angles. While the clouds/etc do stitch ... the illumination of each image varies so that the seams are quite noticeable. I did have radiosity enabled, but Artlantis does auto-exposure which would prevent getting matching images anyway I think.
Attached is a VBE screenshot after having substituted the images via Eric's instructions - looking at a cube corner ... with the lines of the cube clearly visible.
So, there is more to making these sky maps than just panning around...
Cheers,
Karl