As a supplement of sorts to my previous post on the possibility that Earth-Prime will (re)emerge as a (if not the) primary parallel world in the post-IC universe, here is the scene from Infinite Crisis #6 (page 29 in the original issue, page 203 in the hardcover) in which Alex Luthor is searching for Earth-Prime among the newly reconstituted worlds.
I don’t have a scanner so I had to take this with a digital camera, but before he reaches out to the reader, breaking the fourth wall, Alex is saying to himself:
Earth-Prime…
…where are…?
YOU.
If anybody has a proper scan of this I’d appreciate it.
Any Eventuality 
My interpretation of that scene was that when Alex said ‘You.’ he saw one of the Monitors for the first time, which he didn’t expect. I don’t think he ever located Earth Prime.
Interesting… I assumed it was a nod to the famous scene in Animal Man #19 (Grant Morrison’s “response” to Crisis on Infinite Earths) where Buddy Baker suddenly sees the reader and realizes he is a fictional character.
It was also the preceding issue (Animal Man #18) that predicted “a second Crisis” and Infinite Crisis #2 itself opened with Animal Man rummaging through a closet containing many tokens from Morrison’s run on the title, quite an explicit acknowledgment of that series’ relevance to the unfolding events.
You raise some compelling points, with references to Animal Man (which I had forgotten about). With this new information, I am somewhat forced to agree with your original hypothesis – Alex found Earth Prime and broke the fourth wall.
Cool, thanks for saying so!
[…] As referenced in my comment on the previous post, here is the relevant page where Buddy Baker sees the cave drawings and realizes “a second crisis is coming”: […]