Hello,
'Mini cubes' are just smaller versions of the cage (plastic-coated metal) 'cubes' / grids used to create C&C cages. The full-size cage cubes/grids I purchased at Home Depot are approximately 14x14". I have seen cages (photos on this site and elsewhere) with accessories made from rectangular 7x14" 'mini' cubes/grids, as well as 7x7" square cube/grids.
I would love to have either size to create some more ramps, bridges, and balcony rails. If I can't find them made in smaller dimensions, I will cut down large ones and file the edges for safety, but it would be much simpler to find some to buy.
So far I've only seen people mention finding them at stores in the U.S. I'm hoping they are available in Canada.
Photos:
mini cube hay rack-using small, square cubes/grids:
Mini-cube hay rack - Guinea Pig Cage Photos