> package local masters was that you could not change the
> appearance of the site or a subsite by changing the sitewide master.
If all the package local masters sourced the main site master, then this would not be the case.
However, I do like your (and Jon's) proposal regarding changing the behavior of the master tag! My only concern is what I mentioned above:
What if you want file A to explicitly use the site-wide master, and file B to use the package-level master (assuming it exists). In your suggested scenario, file B could just contain "<master>", but how would file A specify to use the site-wide master? Setting the full "src" path to the site-wide master seems clunky and a PITA to maintain.
My main interest is preserving the ability to easily do package-level customizations. I hope this issue will be addressed.