I have some of 20x20mm steel profile laying in the garage, the Ericthepoolboy's engine stand (www.thingiverse.com/thing:2225638) is made of "American" type of profiles... Metric stuff is easyer to get here in Europe...
My design is more simple, no laser cutting, just welding is needed.
My first try doesn't look very good with the tiny EF12, it was made of 180 (1), 180 (2),160 (3),150mm (4) lenght profiles (670mm total). For my EF12 I will recomend 150 (1),160 (2), 150 (3), 140mm (4) configuration (600mm total), the big one will be good for bigger Eric's engines (I think it will need some bigger plate).
M3x10 - 8pcs - 4 for plate fingers, 4 for wheels
M3x10 (or more) hex head - 1pcs for position lock
M3x4 or 5 open end threaded insert - 1pcs - for position lock bolt
M3x20 - 4pcs - for wheels
M3x30 or 35 - 4pcs - for EF12 engine mounting (threaded inserts should make other engines fit too)
M3x40 - 2pcs - maybe shorter or longer for the rotor half handle
M3 nut - 9pcs - 1 for rotor assembly (lock nut will be perfect, bit of super glue will do the job too), 4 for plate fingers, 4 for wheels
M3 washer - 4pcs - for plate fingers
6700ZZ bearing - 6pcs - 4 for wheels, 2 for rotor
Engine parts on the photos will be in update for EF12 soon ;)