Was not sure where to hang this thread - might as well be in TF as possibly relevant.
Here goes - movable free-comb nest block.
Nothing wrong with just a "free-comb nest block" where the bees can build whatever they feel like.
This really does mean free-hand cross-comb, just to make it clear.
The free comb is to be limited to the special compartment whereas standard frames/bars to be used outside of the compartment.
I suppose this can be implemented as few standard frames fused together and the bees can have 100% control inside such block.
The nest block can be still moved as needed within the hive OR moved between compatible hives.
Entire hive box can also serve as as "free-comb nest block".
Because there is observation that such "free-comb nest block" may contribute into mite tolerance/resistance OR overall bee health (as a part of the equation) (page 11 of the PDF listed below - documented 12 years no treatment bee colony).
The ideas are not mine, but from this book where the author implements the ideas after observing the feral bee behaviors (will require auto-translate).
PS: added - if you scroll the PDF all way down, there are hive diagrams and photos of how the "free-comb nest block" was implemented by the author.