I'm not sure if all of you are aware of the fact that Gelphie is actually pretty much canon :)
As can be read on the community profil of the livejournal Gelphie spot (link) there are not only a lot of hints in the book but also did Gregory Maguire admit to it in a Q&A! :D

I quote:

Q: There are many subtle hints in Wicked! at a 'more than friendship' relationship between Elphaba and Glinda. Was this intended, or just accidental? And if intended, what influenced you to create this relationship?

I'll say one thing, which is I think English readers are much smarter than American readers. American...

The idea just came to me yesterday and I had to write it down. Another Gelphie onshot :D

They won’t bring us down

There was a thunderstorm. Dark shadows moved through the houses whenever lightning illuminated the nighttime sky. Thunder strong as hammer strokes shook the very foundations of the Emerald City and rain was pouring from the heavens as if there was no tomorrow. The heavens were crying and had every right to. The nature of Oz rose in protest of the evil and unjust deed committed only hours ago.
Glinda the Good couldn’t remember ever having seen a thunderstorm rage over the Emerald...