Rubberduck and I built one last night. You need:

1 - 2X6 (3ft long)
1 - 2X4 (3inches long)

Screw the 2x4 on top of the 2X6. Drill a large head in the middle of the two for tubes and wires, etc. Mount the engine mount to the front, strap the tank to the board, clamp the board to a couple saw horses, and away you go....

Viper