Here's a crazy thought: video game music. Check out The Black Mages:
(mp3's of first album, direct download):
http://bluelaguna.net/music/bm/mp3s.php
(Youtube video):
http://www.youtube.com/watch?v=q5st0b3ln5U
I have difficulty drawing comparisons between Skyfire and the whole collection of Finnish screamy power metally sorts of bands (Children of Bodom etc) because none of them are half as progressive, and I think a major part of Skyfire's sound is that sort of epic, bombastic quality that can only come as a result of playing like 20 melodies at once, where Kalmah, Wintersun, whatever, have more of a traditional rhythm and lead setup (not that there's anything wrong with that).
And, come to think of it, you can find that in classical music, but I'm by no means an expert on that. I can recommend Sergei Prokofiev, but it's a mixed bag of stuff, not just epic dramatic stuff. Charles Ives' stuff is pretty bombastic, but in that old school horror movie sort of way - good, but not for this thread.
I HIGHLY recommend the Japanese black (sometimes) metal band Sigh. Try their most recent, "Hangman's Hymn." And then try all the rest of their stuff too.