Thanks again Phil. I've read that thread again. I think what I'll do is build a 2x6 cabinet that will basically be two 1x6 cabinets joined together and seperated internally. I can then use this as a mono 8ohm 1x6 or a 4 ohm 2x6, with one Gnome, or a stereo unit with a small stereo class d amp.
Alternatively, I could always just buy another Gnome, so if I needed a more powerful stereo combo, I'll be gnome and dry. Seems to be a bit of a gnome-brainer to be honest....sorry....quiet day in work.
If I'm unhappy with the treble response, I'll build a seperate, stackable, tweeter cabinet with the drivers from the 1x10 and the x-over(s) in the cab.