@kephale Not really our decision unless we want to permanently fork. We csn participate in community discussion if you have a case for different package/class names for Java 3D 1.7's vecmath. I will send you the JogAmp forum thread link when I get to the office.
Regarding extending the Apache Commons Math and/or vecmath types: I favor composition over inheritance. I.e.: adapters to and from ImgLib's chosen vector class (es).