Seems things have moved on already to revision 93012. On a side note, you should be able to incorporate that revision into PV (like virtualbox-bin-4.3.10.93012.ebuild)
From the download page: "Please note that the original 4.3.10 packages (revision 92957) were replaced (revision 93012) due to a last-minute regression, see #12868!"
+*virtualbox-bin-4.3.10.93012 (27 Mar 2014) + + 27 Mar 2014; Lars Wendler <polynomial-c@gentoo.org> + -virtualbox-bin-4.3.10.ebuild, +virtualbox-bin-4.3.10.93012.ebuild: + Upstream re-released 4.3.10 version. +