Whoa! What Pablo suggested is the actuality in most of Western Europe ... except for the word "marriage." In most of those countries, a couple gets legally married at the city or town hall or registry office. They then proceed to have a religious ceremony if they wish. If they don't have a church service, they're still just as married in the eyes of the law.
Of course, what's in play here is the word "marriage." And, yes, it carries with it societal recognition of a relationship, hopefully a loving one. And, yes, many hetero couples and religious institutions are hung up on letting queer couples into the marriage club.
I am fortunate to have legal marriage here in Massachusetts. When people ask me if I plan to relocate to warmer climes in retirement, I tell them in no uncertain terms that it won't be until same-sex marriage is fully recognized in those semi-tropical paradises. So, even if civil unions or domestic partnerships carried all the rights of marriage, I think I'd still hold out for marriage. Sorry, Pabs, but your concept is good, but people want equality ... not just legal equality, but social equality too.
When you can transform the war and violence in yourself, then you can truly begin to help others find peace. Thich Nhat Hanh