Capcom has since released an updated version in English called Mega Man: Official Complete Works for the 25th anniversary. But it looks like it's now out of print so it's actually cheaper just to buy
MM25: Mega Man & Mega Man X Official Complete Works, which is still being printed.
Have you seen thecpoc's custom matching NES covers? They don't use the Famicom art but they still look damn good:
http://www.thecoverproject.net/forums/index.php?topic=368.msg22192#msg22192And if you do end up buying the art book, by all means make some scans, because I'd love to see those covers in the deviant art link remade as full size UGC or CGC covers. It looks like the artist made those as mini boxes, maybe 3/4 the height of a normal NES box. I thought about contacting him, but looking at his page, it looks like he's unwilling to share full versions of his art for fear of it being sold on eBay. Oh well, can't blame him.