We are thinking of creating a 'Sandbox' community, would this be useful?

The idea is:

* You can experiment with Q&A, not just chat
* Everything would work as usual, voting, flagging, notifications etc, for experimenting with all aspects of the site
* It wouldn't be public, that would be a confusing mess, so you'd need to ask to join it
* Any post types available in other communities would be added on request, so you can play around with how they work before deciding if you want them in your community (this is what prompted the idea, as some people in tex.se are wondering if a 'concept'-style post might work for them there)