Not really, but mainly by virtue of the fact that Scrivener doesn’t work in pages to begin with. So it’s kind of hard to have different page sizes when you don’t even have pages!
But if you mean mainly just making the editor wider now and then, try turning off the fixed-width setting in the Appearance: Main Editor: Options preference pane. There is unfortunately no convenient toggle for that, so if you generally prefer a sensible line width while editing, you could consider leaving this setting off, and making use of the “Page View” mode, in View ▸ Text Editing ▸ , which has a keyboard shortcut.