Palmtree is both responsive and also converted to the new theme framework.
That is also the "primary" theme for NetTalk 12, so the one I will treat as the "reference" theme. (In other words, if you are going to make your own theme, it's a good one to start with, and also a good one to keep comparing against to see what new stuff has been added.)
Given how easy it is not to change the fundamentals of a theme (using the Themer example) that's probably a good place to start.
ShoeStrap1 and ShoeStrap2 are also converted already to the new framework. that's in the 12.05 build.
12.06 will include the Base theme converted (that's done already), and perhaps one or two others.
B