As agreed with mraudsepp on IRC, I attach here the unified eclass and proof-of-concept ebuilds for gstreamer that I was working on because I thought gstreamer@ was on slack-leave :-)
Created attachment 188227 [details] tar of the directories
Created attachment 188229 [details] easily-clickable version of eclass
Created attachment 188233 [details] gst-plugins-base-0.10.21.ebuild Example ebuild for one of the media-libs/ ebuilds.
Created attachment 188235 [details] gst-plugins-cdparanoia-0.10.21.ebuild Example ebuild for one of the media-plugins/ ebuilds
Some comments - the strict dep should only be on DEPEND, Gst guarantees that the RDEPS should always be >= (in theory, that would also be true with the build-time deps, but no one checks). - the glib dep is at 2.12 I think, definitely not 2.16 - this ebuild wont work with the media-libs/gst-plugins-{base,good,bad,ugly} packages... in that case, you want to build everything in common/ docs/ gst/ and gst-libs/ at the very least - We're still not able to run the tests, which is sad (because except -bad, they're all guaranteed to pass).
Oh I missed this completely :( I did a rewrite of eclasses currently being reviewed on gentoo-dev ml. Please have a look there.
New eclasses have been commited to tree. If you still have problems with eclasses, feel free to open a new bug report.