Have an odd situation and am not sure what caused it. I have a full sandbox (CS5) which was provisioned approximately 2 months ago from a new UE production site, at which point Communities was enabled in it.
Today I happened to notice that Setup > Develop > Sites is not available in this instance, which means I am not able to provision a new Force.com Sites instance (other than by the "bundled" Site you get when you create a new Community).
However, in a recently provisioned "developer pro" sandbox from the same production org, which had the same setup starting point (no Sites provisioned, Communities not enabled), after enabling Communities and provisioning 1 Community, I was still able to see Setup > Develop > Sites.
I'm trying to make sure that when I enable Communities in production I will still have access to Setup > Develop > Sites. I tried this today in a brand new provisioned developer sandbox from another UE org that did not have Communities enabled, and I did still get Setup > Develop > Sites.
Has anybody seen the behavior of Setup > Develop > Sites disappearing, and know how/why? Is it possible that Salesforce is planning on end-of-lifing free non-Community Force.com Site instances?
I've filed a case as well, and will update in the event I get a helpful answer.