Okay, it seems to be a little more clear how this is going to work now. Earlier, we figured that Capcom got the Mega Man #51 preview after the previous Worlds Unite solicitations had been released in massive groups, and the rest would come as such. Nope.
Looks like it's coming piecemeal, at least for July's issues! So here's Newsarama's exclusive solicitation for Sonic Universe #78:
SONIC UNIVERSE #78
The third and final act of the EPIC SONIC/MEGA MAN CROSSOVER EVENT begins here! "Worlds Unite" Part Nine: Sigma has begun his conquest of ALL the worlds. Now it’s up to Sonic, Mega Man and X to unify those worlds AGAINST Sigma! It’s a “who’s who” of SEGA and Capcom heroes answering this important call to arms! But with Sigma still active on the unified world, he turns his gaze upon those left behind..! Featuring the worlds of STREET FIGHTER, SKIES OF ARCADIA, NiGHTS INTO DREAMS, OKAMI, GHOSTS 'N' GOBLINS, ALEX KIDD and more! Plus cover art from the legendary Patrick "SPAZ" Spaziante, and variant cover art from "Worlds Collide" penciling star Jamal Peppers and part 9 of the epic 12-part connecting variant cover series by artist Ben Bates!
Script: Ian Flynn
Art: Tyson Hesse, Jim Amash, Jack Morelli and Matt Herms
SONIC UNIVERSE #78 CVR A REG: Patrick "SPAZ" Spaziante
SONIC UNIVERSE #78 CVR B Variant: Jamal Peppers, Jim Amash and Matt Herms
Epic Poster Variant (pt9 of 12): Ben Bates
On Sale Date: 7/22 32-page, full color comic $3.99 U.S.
We'll keep you posted as more parts are revealed. The Mega Man Network: Trawling the far reaches of the internet so you don't have to!
...with thanks to The Fat Panda for finding this one.