Hitoshi Ariga, creator of the Rockman Megamix manga series, recently updated his personal blog to include a few mock up sketches for the new Megamix in the works. According to him, a release date is coming soon.
As for pricing, Ariga mentions the book is planned to retail for 1,524 Yen+additional tax. (roughly $15). He apologizes for the high price, citing it has something to do with the overall size of the book (reported to entail 300 pages) and a limited amount of copies available from the get-go. Apparently, the popularity of other books pose a threat to Megamix's sales.
All in all, expect to hear future Megamix updates soon.
Thanks, Rock Miyabi