After addition of the jit flag to webkit-gtk-1.2.6 (which is disabled by default on hardened), Midori works fine without disabling MPROTECT (tested on hardened x86). Relevant bugs: bug 338213 bug 344177 bug 338561 Since webkit-gtk-1.2.6 is now stable on x86 (and I assume that other archs will follow), I think that the pax-mark addition in the ebuild (introduced due to bug 338561) can be reverted.
+*midori-0.2.9-r1 (16 Jan 2011) + + 16 Jan 2011; Samuli Suominen <ssuominen@gentoo.org> +midori-0.2.9-r1.ebuild, + midori-9999.ebuild: + Don't disable PaX anymore wrt #351407 by Faustus.