Wow that's a big horse !! Is she for riding? Or for moving buildings?
I got a quarter horse named "Dan". Real imaginative name there huh? (No, I didn't name him} So as to names for her, here's some suggestions:
Djam Karet
Galadriel
Amazing Grace
Siberian Khatru
Shadowfax
Xanadu
or any one of the many strange Ozric Tentacles song names.
Best of luck with her !!