A new version of dev-ruby/sass has been available since 15 Aug. I've bumped the ebuild locally and it is functioning properly, but haven't verified that the dependencies are still correct for the 3.2.* series. I don't see much point in attaching what I've got, since it's an exact copy of the existing 3.1.21 ebuild with a bumped version, but will be happy to do so if requested.
According to our pending bumps list at http://wiki.gentoo.org/wiki/Project:Ruby/Pending_Bumps#sass_3.2.1 these versions fail tests for JRuby. That needs to be investigated first.
Upstream can't reproduce this and it only affects debug output in the CSS file, so I've added sass 3.2.3 to the gentoo tree just now.