Subject says it all.
I don't have time for this myself but if you want to drive it I'll help you.
I'm closing the bug as currently there is zero time I can put on this. If someone is interested in it feel free to jump in with work towards making it happen.
Just putting some comments here for posterity:
eclipse is in the devtoolset-3 SCL. It requires some extra packages to build: decentxml, tycho, tycho-extras and xml-maven-plugin. We may need to bootstrap a minimal environment with at least these packages (and any deps - possibly eclipse-platform) to ease building of extra eclipse packages against the devtoolset-3 scl.
I've filed bug 1166348 for building tycho for EPEL7.