There is at least one trailer of similar design in the US - I helped
rig a Ventus (?) out of it at Turf Soaring (Phoenix, AZ) back around
1999 or so. Beautiful construction, fairly easy to use (but no better
than a Cobra, really).

I think it would make it almost impossible to use a one-man rig, since
it looks like you can't roll the root out solo.

And HEAVY! Lots of steel involved.

It does make a great picnic/work bench/bar when the glider is rigged,
though...

Kirk