I am still using Volume Logic through Audio Hijack Pro on Yosemite; it's slightly inconvenient, but actually expands the original functionality of the plug-in by allowing you to process any app's audio with it. If you still have an old installation of Volume Logic and the old version of Audio Hijack Pro (the new version doesn't support the iTea plug-in) you can use them to tide yourself through…
That being said, I'm one of the hordes of Mac users who have been waiting for a version of Breakaway that we can use for years! If you build it, we will come!