Hi James
Gosh you are sharp - I had not spotted that before. I cannot recall such an accessory although it would be useful.
There is no MFT3 accessory like this but there is one for the Precisio, part number 488064. The sizes could be all wrong of course.
Quite a few manufacturers use a pair of wheels on a fixed axle that requires the tool or bench to be lifted slightly before the wheels engage with the floor. I would think that it would not be too difficult to make one from scratch. It will not have to be especially strong as the MFT3 is not that heavy.
Peter