I was hoping to find a way to disable particular extensions on a theme by theme basis?

Hypothetical scenario:
I would like to develop a mobile theme for my existing magento website.
The site has a number of extensions that don't play well with my mobile design.

Instead of re-working all of their css/template files I'd prefer just to revert back to magento's defaults.

Is there a way perhaps within /design/frontend/mypackage/ where I can disable those extensions?