By any chance have you been able to resolve this issue...it seems like I'm having the same one, and the last two hairs on my head have been anxiously awaiting a follow-up in this thread
Likewise, my param.ini is unwritable (though I manually change the rights on it...it reverts back to its previous state as soon as I apply the template changes...but that doesn't stop those changes from being written anyways)
This might be a clue:
When I use firebug to inspect the site's elements it seems like all the styling is stored in a temp php file with some odd name, eg., http:/mysite.com/templates/rt_quasar_j15/lib/gantry/css/css-acd28a5b530f70115931324b4f6a2a7b.php
on my localhost, pointing to the same element will refer to style2.css
BTW, deleting the those php files does not solve the caching problem....nor will changing the template.
There's a brut force way to solve the problem: reinstall Joomla!
Uploaded a fresh version of index.php and it worked.
No idea whats different except that instead of adding a new div called footer-wrapper I simply moved the div around. Basically the same thing without the new wrapper so can't see why it would work now and not before.
Unless the caching issue has simply resolved itself....