Where can I find detailed information about Responsiveness of WPMU themes-viz which themes work well

Hi,

There are a ton of themes created by WPMU- but only since the last few years has responsive design become really important due to exploding usage of mobile and tablet devices.

What I wished to know is, which all themes (whether for Wordpress/Marketpress/Buddypress etc) support mobiles/tablet devices in addition to PCs/Laptops.

Also, is the above information available in detail for each theme- for eg. the much higher iPad Retina resolution is very recent- even a lot of responsive themes don't have support for that kind of resolution... Is there some way to know (for eg) a list of mobile devices on which any WPMU designed Theme looks/renders well?

Yours sincerely,
Arvind.