I've just privately released a stripped down version of my WordPress framework aimed at designers looking to build responsive wordpress themes, but unsure how to get started.
Skeletonised is a WordPress Starter Theme based on the Skeleton responsive framework and a stripped down version of my own little WP framework: Use it as a starting point for developing your own responsive wordpress themes.
I won't go into too much detail here about it, if you are looking at designing WordPress themes and are interested in a responsive theme base, this is probably interesting for you. It's a clean and tidy base theme bootstrapped with menus, widgets and various WP standard features. It's a blank slate on which to build your own wordpress themes.