Looks like volume one of Mega Man Megamix is coming with a few extras directly from its Japanese counterpart. Amazon's listing now reads:
" Because you demanded it! The manga adventures of Mega Man - available in English for the first time! Witness the origin of Mega Man, his first battles with Dr. Wily and the evil the Robot Masters, plus appearances from Dr. Light, Roll, Proto Man, Rush, and many more Mega Man favorites! Also included in each volume are character profiles, sketches, and creator interviews."
All in all, volume one seems like a pretty nice deal for $12.95. More Megamix details are coming soon!