As has been posted before, there already IS a Europea Cockpit Association. As of now, membership is open to pilot associations, but there are thoughts on how to improve on this and how to better accomodate trans-national airlines like EZY (already in progress) and Ryan (tougher).
Lots of thought is given to how to prevent P2F, the current move to more contract work, etc.
Many smaller associations would love to give ECA more power and make it a real union. Many bigger unions (UK, Spain, Germany, France) object to this as it would take power away from them.
ECA is far from being a union but it could become one, if the pilots of Europe wish it to be.
One should, however, not be too optimistic about this. While ALPA International has but two countries, two similar legal systems and effectively one language to deal with, Europe has 27 legal and tax systems and almost as many languages. That makes imposing uniform contracts a lot more challenging.
Whether it is ECA or BALPA, we need to stick together and convince our brothers that they better stick together with us, too. This is the only way to save and improve our profession.