I wouldn't mind seeing a Justin Hartley Green Arrow series, I can see the upcoming episode featuring Speedy (Mia) setting up a spin off. We have also discussed before the possibility of a Legion of Superheroes spin off as well. Although I think it could have the problem of easily being the CW's most expensive series, the characters fit their demographic and their motto of airing shows to a young and "kewl" audience. I would establish a pilot featuring Rokk, Imra, and Garth and then add three more core members including Brainiac 13.
Christopher's suggestion of Tales of Asgard (Marvel is doing a animated series with a young Thor btw Chris in 2011 called Thor: Tales of Asgard) reminds me of Young Hercules starring Ryan Gosling.