there is dev-ruby/ruby-panel-applet which is for gnome1. in ruby-gnome2-all sources, there is panel-applet directory for gnome2.x I just copied ruby-pango's ebuild and modified dependency and description. It installed successfully.
Created attachment 62987 [details] new ebuild
for those who want to use this, and have it work, call it dev-ruby/ruby-panel-applet2-0.12.0.ebuild
I've just commited all the packages from ruby-gnome2-0.14.1, including ruby-panel-applet2. Sorry it took so long...
Hmpf, forget to mark fixed, sorry.