Blink is an excellent SIP2SIP and is available for free on Ubuntu and Windows, the Source is Fully GPL, but the lite client on OS X is 24.99 and the Pro is 64.99 WHOA! Why pay the mac tax on a GPL Client
So Since the sources were available I am making available Blink Pro on the Bug Shop Compiled for 10.10 on Sources downloaded on January 3.
You can of course still buy the Blink Pro or Lite App on the App store, if you like it, buy it, I suppose, to support development.
Of course my app is not signed or anything like that so OS X will throw a bunch of errors about it being untrusted.