Mobile second... any way to change the order of adaptive stylesheets?

Issue Summary

Sometimes it's too much to ask a large institutional client to think "mobile first". In my experience, all clients think desktop first with mobile as an afterthought.

Unfortunately, the way style sheets cascade in Omega assumes that you're taking a "mobile first" approach with the following order:

If you take a "mobile second" approach this means that you have to set your mobile styles in global.css or mytheme-alpha-default.css first, then apply your desktop styles in -narrow, -normal, and -wide. This makes for quite a bit of extra coding and shiffling around of styles if the mobile design is created after the desktop design.

Also, using alpha-default as a name for the stylesheet that is used for widths under 740px is not obvious... could that stylesheet be renamed mytheme-alpha-mobile.css or mytheme-alpha-extra-narrow.css in the Omega framework? It would be far easier for themers to understand.

Can Omega be set up in a way that allows for different cascades for the style sheets through the UI? Here are two examples that would work better for a mobile second approach:

This would make Omega far more flexible and adaptable to different circumstances that fall outside the "mobile first" path.