As some know from #maemo I've been working on getting fennec-14b7 to build with qt/thumb2/NEON which I believe is a supported target for the JavaScript JIT (as it's what get used in the Android build) along with the features from the Harmattan build utilising qt-mobility for system integration.

So far, with a couple of code tweaks I've got it to build against libqtm-12, it's not perfect, screen auto-rotaion is off by 90º, keyboard handling isn't quite right, but it is FAST, and memory utilisation is much better than earlier builds.