Not in the user interface. Maybe with a script?
@babs – even with a script this is not possible. It's a restriction of the UI.
You can either select all guides or select all page objects.
Of course, by scripting you could address all guides and move them around by changing their location property.
And in a second step you could adress all other page objects, scale and move them.
The margins with all their properties (another kind of guides) have to be addressed in a third step.
But by scripting there is a more powerful way of scaling a page with all its guides, margins and page objects.
Marc Autret did a blog posts on this more experimental feature.
The script he is showing there ("TransformSpread.js") does transform the VIEW of your spread in InDesign, not the output. So it may be of no immediate practical use for you.
Another blog post deals with a more practical transformation of page objects. Guides and margins included.
So I think "TotalRescale.js" would be the one for you:
After scaling the contents with "TotalRescale.js", you "only" have to scale the pages.
Of course the main problem is to find the right reference frame for the scaling, if you do not want stretched objects.
One hint in this regard:
set the margins to "0" before using the script…