Created attachment 394630 [details] ruby 2.2.0 proposed ebuild for prefix I had to mask virtual/rubygems-10 because prefix is missing ruby-2.2.0, so I figured I might as well see if I could get ruby-2.2.0 working on prefix. Prefix is also missing ruby-2.1.5, so I diff'd prefix's ruby-2.1.1 and upstream's ruby-2.1.5 to try to isolate the prefix specific changes. (ruby215-vs-prefixruby211.diff) Then manually I applied the prefix-specific diffs to the upstream ruby 2.2.0 ebuild and came up with the attached ruby-2.2.0.ebuild, which it seems emerged successfully on my OS X 10.8 prefix. (ruby-2.2.0.ebuild). The diff between upstream ruby-2.2.0 and my proposed prefix ruby-2.2.0 also attached (ruby220-vs-prefixruby220.diff).
Created attachment 394632 [details] upstream ruby 215 vs prefix ruby 211
Created attachment 394634 [details] upstream ruby 220 vs proposed prefix ruby 220
This sounds like a reasonable request (especially since 1.9 is going away soon as I understand it). Have you tested switching between 2.0 and 2.2, gems, etc?
dev-lang/ruby-2.2.1 is in Prefix now