There were some efforts building node-webkit for pi, but haven't heard were there any successes. You can find some info on the nw mailing list.
Regarding pine, i was following their git few months ago, druring the ownership transfer between some guy that started pine and the current maintainer but haven't seen any updates in months. @thehen did you hear some fresh news about the pine project?
I have one pi for some time now, but i didn't really succeed in running an c2 app with decent results. I tried html5 export, with standard pi linux and chromium for pi. If anyone wants i run some test on pi, please contact me!
Be nice until it's time to not be nice