"What is it with billionaires being superheroes?"
"All Star Team-Up"
This was a meta-joke in which the most O'Bvious allusion would be to Bruce Wayne aka the Batman, since the Caped Crusader is from DC - the same comic book company that publishes the adventures of Green Arrow.
And if Caitlin knows about Bruce Wayne and Batman, then it supports my theory that Batman was of a previous generation. And that he had hung up his cowl and went into retirement - in such a way as to also announce who he really was under the mask. (Perhaps by way of an autobiography?)
The thing is, 'The Flash' and 'Arrow' both take place in Comic Book Toobworld rather than in the main Toobworld. There's a possibility that one day the Batman may appear in either one of those shows. As to whether the Batman would be from the movies - about to be played by Ben Affleck - seems unlikely. While Marvel has been able to meld its cinematic heroes with their Television spinoffs fairly successfully, it doesn't seem so likely with movies that have so much turnover in casting. DC may want to keep their movie superheroes separate from their TV heroes.
As for Earth Prime-Time, Bruce Wayne did retire at some point in the early 1980s and more than likely he was replaced as the Batman by a succession of others - perhaps first by Dick Grayson. And as for Superman, he died in the early 1960s due to radiation poisoning.
Meanwhile, let's get back to what Caitlin said. Remember what Caitlin said? It's up there at the top of the page.
Based on mentions in other TV shows, Batman is known to have been billionaire Bruce Wayne in the main Toobworld. But that is probably not the case in Comic Book Toobworld. So it could be that Caitlin wasn't referring to Wayne.
Maybe she was referring to Tony Stark, aka Iron Man.
Stark is known to be Iron Man by the general public, and he loves the adulation which ensues. And the fact that Ray Palmer wears a super suit of pure techware probably brought the comparison to mind for Caitlin.
The A.T.O.M. may be from DC and Iron Man is from Marvel, but both are in Comic Book Toobworld and so Caitin Frost woud be one of those thousands who knew of him. (Iron Man hasn't been seen on the small screen yet, athough his movies have been absorbed into that TV dimension.)