I've been tracking this one down for years. I could've sworn I had this on VHS somewhere, but it looks like somebody beat me to the punch. Nevertheless, lo and behold: the very LAST televised Mega Man commercial to air in North America.
The spot, arguably of higher quality than previous North American Mega Man commercials, aired in late 2005 to advertise Mega Man Zero 4, Mega Man Battle Network 5 DS, and Mega Man X Collection. Rarely was the commercial shown outside of family-centric networks (Nickelodeon, Cartoon Network, Kids! WB), but I do recall catching this on TV Guide Channel at one time.
Since '05, no other Mega Man commercials have aired here (and no, Volnutt's TvC cameo doesn't count). Meanwhile, new commercials continued to be produced with every Rockman title released in Japan, although the momentum cooled just recently.
While it is true a pseudo-commercial was created for Mega Man 10, it did not, however, air on TV. Shame, really, because that would have been mighty awesome.
I guess somewhere along the line Capcom felt the need to pull the plug on televised marketing. Certainly hope we'll see another one on our air waves someday... I'm looking at you, Legends 3.