Which Protestant churches as of today officially recognize homosexual marriage unions? Is there any such information available?
I think these are the same churches that approve ordination of lesbians. You can find a list here.
When reading the list keep in mind that some traditional churches have a wide range of different churches under the same umbrella. For example, one Lutherian or Anglican church might openly preach against homosexuality of any kind, while just a few blocks away, another might ordain a lesbian as their rector or senior pastor!