Paul a Lunn seems to take a broader view and seems to quite happily come up with micro designs that are 6 x 2 in some cases. In my eyes it is about being self contained, portable and easily stored.
My 6x1 I have posted as a micro using these criteria to justify it to myself, sorry if it is in the wrong part of the forum. My inspiration to actually build came from Carl's p84, Northleigh, a 4 foot layout with a 2 foot fiddle yard he adds defensively.