And now all bets are off.
According to Variety, Aquaman has been picked up as a "put pilot": A deal to produce a pilot that includes substantial penalties if the pilot is not aired; a virtual guarantee that a pilot will be picked up. In other words, the odds of Aquaman becoming a series just went WAY up.
Additionally, the Variety article has more tidbits about the pilot, including that Greg Beeman will direct the pilot, it will be set in the Florida Keys, and the Bermuda Triangle will be an active part of the stories. Also, Aquaman will never be referred to as "Aquaman" (as Smallville never refers to Clark as "Superman") and Aquaman won't be talking to fish.