Below are links to photos of a playscale boxing ring produced by M&C Toys under their Star Runner line for Vanessa and for anyone keen on creating such an arena for their dolls and figures. I did not buy the boxing ring or the gym or - alas - more than ONE of the Star Runner action figures, but I do wish that I had bought some of the other guys.
Here are more photos ...
the boxing ring itself
two figures in the boxing ring
I don't know anyone who has this set, but the photos might stimulate ideas on how one manufacturer created a 1:6 scale boxing ring.
Happy creating! Do share the link(s) if you create a boxing ring scene.
P.S. The post for SkipperCollector is post-poned (get the joke, lol) because the photos need to be clearer.