Could you maybe install rings from a ceiling? or any other point? you could do pull ups on those, and a bunch of other things. Though, if you can drill into the ceiling you could also just get a pull up frame that way.
I think you might just have to build your own with pipes and stuff like that, you could manipulate just about all aspects of it and make it fit your needs - maybe enlist the help of someone that's good with their hands and is creative enough to envision how it should come together.
I'm also a little confused on why you can't do circuits at the playground? I guess you mean circuits requiring weights? You could do pull ups, dips, hanging leg raises, run/sprints, bodyweight squats (single leg or standard), static holds, etc at the playground.
I can't think of anything else, sorry.
Edit: they wouldn't have to be rings necessarily, you could just get a stick and some rope and make a pull-up bar (trapeze style!) but if you're drilling you might as well get the most bang for your buck with a good pair of rings.