According to executive producer Marc Guggenheim, we might actually see Green Arrow team up with Batman in the new CW series Arrow! This would be extremely cool! This is something that we never were able to see happen in Smallville because of Christopher Nolan's batman franchise. Now that Nolan's Dark Knight franchise is over, the CW might be able to use the character in their TV series.

Here's what Guggenheim had to say in a recent interview with IGN when asked about seeing any DC universe allies in the series,

I would say, “Probably.” One of the things we want to do is roll the show out at the right pace. For the most part, I think we’ve taken the philosophy that things are happening sooner rather than later. I always feel like every time we get the note from the network, “Is this happening too soon?,” I feel like we’re on the right track. I know as a viewer myself, I’m impatient. I want to see stuff. We’re not going to make the audience wait to see characters, plot twists, revelations. I think running out of great characters and great moments is a quality problem to have, and I just want to have them.

He's then asked specifically about Bruce Wayne/Batman making an appearance in the series to which he replied,

Oh, my hope is that we can use him at some point. I think that plagued the Smallville showrunners more than it plagues us because, obviously, the Dark Knight Trilogy is over. They’re not available to us yet. My hope is that they’ll be available to us at some point. That would be awesome. No question, that would be absolutely awesome. But I don’t know. That’s above my pay grade.

It would be so cool to see something like this happen. I don't see why they wouldn't do it as it would most likely give the show major boost in ratings. Fans would love to see Batman team up with Green Arrow!

It was also recently reported that Green Arrow villains China White (played by Kelly Hu) would appear in episode 2 and Deadshot (played by Michael Rowe) would appear in episode 3.