While we eagerly await further news from Coro Coro Comics' much hyped mystery Rockman title, I figured I'd go ahead and analyze this famous picture used to promote the boss contest in a number of occasions (here and here). A common belief is that the image, featuring the profiles of four Rockmen, was created specifically for the contest and subsequently, the new game. However, upon further investigation, this assumption might not be correct as each of the profiles have been seen somewhere in the past.
Let's start off with classic Rockman's profile shall we? This particular profile shot actually hails from classic series reference materials used when developing all sorts of heroic poses and the like. You can find this picture on page 248 of R20.
Moving along to X's profile. This one should be familiar to you as it can be seen on X8's title screen and in numerous promotional artwork (example).
Next up, Rockman.EXE. At first, I thought that shot came directly from the "EXE4/4.5/5 soundtrack", but upon further investigation, I realized it comes from a non cropped version of EXE 3's box art (picture).
Last but not least is Shooting Star Rockman's profile: It looks a bit like a similar profile shot from SSR2 (picture), but that Rockman notably lacks the white "neck stripes" and flattened earpiece featured on the boss contest splash. New art perhaps?
Whatever the case, the boss contest splash is certainly interesting. Does it merely represent he boss contest or is it hinting of some sort of crossover? Only time will tell.