Other Z-level locations?

[DarkStar]

I know this is sort of 'out there' but I always wondered if a single Z-level could have persistence between rounds, with the caveat that small/tiny items not in a container were wiped between rounds (to prevent piles of glass shards or the like from creating Lag-O-Death) and certain blacklisted items in or out of containers.

Basically a place where you can build your own autism fort or wire art but not hoard crates of phasers or Solarium goodies. Your own little corner of the universe.