Oh, it's been screaming obvious. Glenn Close even said in an interview somewhere that she was kind of playing it like Patty was seducing Ellen in the pilot. Also, Patty has been very patient and supportive of Ellen even after Ellen brought her Katie Connors, and we know that Patty isn't the snuggly type, which gives a very slashy vibe to her fondness of Ellen. That combined with Ellen's hero worship (I think this is a far better example of a "school girl crush") makes their relationship so gay.

I mean, they could have at least played around with the sexual undercurrent between them but didn't have them consummate that would have been something. Patty touching Ellen, or them holding each others gazes for a bit too long, them standing a bit to close, or leaning over the others shoulders a bit too close, Patty using Ellen's infatuation to manipulate her would have been so awesome.