I make my own transport cages using a 24x24 cage pan as the base, then I build a 23x23" cage using 1x2" cage wire. I use 1 x 1/2" cage wire for the floor and raise it about 2" from the bottom of the pan so my buns aren't sitting in their messes. The rest of the cage is about 10" tall and features a center divider, creating space enough for two rabbits per carrier - or roughly 23x11.5x10" per rabbit. I have previously made my dividers out of cage wire, but I am planning to change them out in favor of solid dividers soon. I don't think my rabbits will breed through the wire, but stranger things have happened. Also, solid dividers prevent bucks from spraying pee on each other and making a helluva mess to clean up.