Solfege can be bumped to 2.0.5 with minor changes to the ebuild. I will attach a 2.0.4-->2.0.5 ebuild diff. I've changed python dependency to 2.3 (now required), and docbook-xsl-stylesheets from 1.62* to 1.6* (works fine with 1.65, and fix an emerge upgrade/downgrade loop for ~arch users since 1.65 is now in portage). Side note: I've left the oss USE flag disabled for safety, despite I've not been able to reproduce bug #43889. Anyway, that's really not important to be able to switch that off, so that's perfectly fine this way.
Created attachment 36253 [details, diff] solfege_ebuild-2.0.4_to_2.0.5.patch
why did you remove ~amd64?
in portage.