Amazon has posted a pre-order listing for the fifth Archie Mega Man trade paperback collection, titled "Mega Man 5: Rock of Ages" for a retail price of $11.99 USD. However, it isn't due for release until June 13, 2013. That's quite a ways off, but I suppose it couldn't hurt to reserve a copy now.
No solicitation available at the moment, but we can assume the book will collect issues #17-#20 (“Proto-Type" part 1 and 2, "Roll With It!" and "Rock of Ages"). If past TPB's are any indication, expect even more bonus content and a collection of variant covers. Fun stuff!