(This sounds like I task I might get stuck with attempting some time.)
I haven’t thought the whole way through this, just kind of brainstorming:
Use a large, sturdy
base (like 4’ x 4’ of ¾” plywood or maybe you need to
build a bigger, common
base/
platform) and mount the lamppost in the center (Sorry, no ideas for that.) (Deep down inside, I think something involving welded steel is needed….)
The big issue is what kind of swinging is involved. If it’s just the dancer holding the post with one
hand with the feet close to the
base and not too much speed, the above may work with the dancer’s weight holding the post and
base down and the
broad base to keep the whole thing from tipping. (Would also depend on the size of the dancer.) Or if it’s just holding the post, but dancing around it (an illusion of actually swinging), with the dancer’s weight on the floor, mostly, then the above should work.
Now moving it will be a chore, but I like that tip-up-onto-the-wheels idea in the post above.
Another consideration is whether the dancer will actually be swinging all the way around the post. That is, if the move starts from one side and only goes through, say, a quarter of the circumference of the post, you only need solid support from those angles. (Although, during practice, the dancers may try to do more with the post that intended.)
[I’m not familiar with using marley, so the above approach may beat it up.]
Joe