Hi,
I find the respond-to() syntax used for instance by http://breakpoint-sass.com/ very handy: it improves the readability of the scss code and I am also quite used to it, so I would like to have it available in megatype.
I have a prototype already, I am going to send a pull request for review.
AFAICS it's not advisable to use breakpoint-sass together with megatype because that would introduce inconsistencies wrt. the root fontsize, so the support has to be added to megatype itself and based on the `media()' mixin which handles the root font size change.
Ciao,
Antonio