If anyone has access to a 3d printer there are lots of axle mounts available via yeggi.com. I made a basic rack for my van (VW Caravelle) using a couple of the mounts shown below (both modified slightly to have a larger base height to stop the handlebars clashing) and a length of wood across the back of the van.
This allows me to easily fit 2 x Levos slid in backwards with the front wheels removed and 2 x (almost full size) kids bikes in forwards with wheels still attached. A few bungee straps and all is secure.
The rack I made does not fix to the floor in any way and is still really secure once the weight of 2 Levos are bolted to it through the fork mounts.
This allows me to easily fit 2 x Levos slid in backwards with the front wheels removed and 2 x (almost full size) kids bikes in forwards with wheels still attached. A few bungee straps and all is secure.
The rack I made does not fix to the floor in any way and is still really secure once the weight of 2 Levos are bolted to it through the fork mounts.