Maybe?

but these were a little higher than leveling ramps I've seen and they give a "flat spot" or an area where everything comes to rest.

I particularly liked the idea of there simplicity and ease of use. Apart from having to have the strength (or leverage) to undo your lug nuts they almost seem too easy to use.

I can imagine numerous situations where a Trailer Aid would be so much safer and easier to use that a conventional jack (soft or sloping ground, not physically able to use conventional jack, etc).

I sure if you've got the time, inclination and tools. It wouldn't be hard to make on of these as well

This ramp idea is a great idea BUT its another bloody thing to store away and carry.Might have to leave the cook home if I keep buying all these gismos.

On my tri axle van on the chassis next to the mud flap is a support bracket that the wind up jack attaches to. I just clip on the jack and wind up until level. To check if the van is level I use a 4foot spirit level. I level it length ways using the jockey wheel and the wind up jack for levelling cross ways.