X Dome 1? X Mid 1+?

How come there is an X Mid 1 but no X Dome 1? or...how come there is a X Dome 1+ but no X Mid 1 +? Got to wondering not because of weight but ground area taken up for small tent sites. I would be interested in an X Mid 1+ if it was produced as I love my X Mid Pro 2 but I think it would be better if it was a bit smaller but not as small as the X Mid 1.