Oh, I screwed up. I didn't mean to combine them, I meant seperate themes. S'why Pi-r-squared said no.
But honestly, you've got better source material if you chose Dr. Wily instead of Sigma. The Mega Man 3, Mega Man 4, Mega Man 6, and Mega Man 7 Wily Battle themes are much better pieces that most all of Sigma's battle themes.
Mega Man 3: http://music.atomic-fire.com/mp3/src_org_rm3/21%20-%20Final%20Battle.mp3
Mega Man 4: http://music.atomic-fire.com/mp3/src_org_rm4/27%20-%20Final%20Battle.mp3
Mega Man 6: http://music.atomic-fire.com/mp3/src_org_rm6/24%20-%20Final%20Battle.mp3
But with you up to four minutes? That seems like a -lot- of work to abandon, so.