Could you use Windows RT in potrait mode?

(non-native speaker here, please excuse my grammar)

I am in the market for a tablet, watched few Surface videos, none displaying portrait mode.. Is it possible?

Also just an extra thought, would the Windows tablet really need the top and bottom bezel then?

My nitpick is the screen for Surface and upcoming Windows 8 tablet have this long landscape dimension.

Is it already a determined specific ratio, and could OEMs make wide range of dimension a la Android?