I built one out of 1/2 inch 9 ply plywood and 2x3 lumber, with 8 inch lawnmower wheels and levelers (3/8-16 steel rod, 10 inch long). Fairly easy and quick to build, it 32 inches on a side, it was meant for my Avalon M-Uno with TPod 110 but could be used with the M-Zero Obs.