I'm not sure if this is what you're looking for, if not, Matthew's comment will probably suffice. Anyway, my comment relates to using the Page Selector from a custom module. Since I could not find how to do this, I figured I'd post that here, even if it is in the wrong forum (3.x). My comments are related to developing in Sitefinity 5.
I had the requirement to reference a single page in the site hierarchy from my custom module's content items. I utilized the PageFieldElement control from my modules definitions to accomplish this, as well as couple other pieces of code.
My content item has a property called PageGroupID. It is a Guid. There is nothing fancy about it in the least, it's just a standard property defined in the following way within my content item class (in this case ParternItem.cs)
Then, in my definitions class, I have the following code, within the CreateBackendSections method, when I'm adding all my fields to my detail view:
I've specified my RootNodeID as the FrontEndRootNodeID, so you may want to change that, but, that seemed to work for me. I am able to select a page and it remains after save. Hopefully this is of help to someone.
edit: you'll probably want to change the CSS class, and my title is referencing a junk resource that I just left in there for testing... you'd likely change both of those anyways