I read online that according to Wizard's April magazine, Arad mentioned that the plans for spin-off movies at that point were:
Wolverine
Magneto
and Rogue, which is in fact the current name for the X-Kids film.
Wolverine will deal with flashbacks in Logan's life from before he had adamantium, and up to the point where he met Rogue in X-Men 1. Hugh Jackman is signed up for this role.
Magneto obviously deals with the villain's past, and dealings with the early X-Men possibly. Ian McKellan is supposedly signed on for this.
Rogue's movie will feature Rogue, Gambit, Iceman, Kitty, Jubilee

, and Colossus... and will deal with these younger X-Men and their daily lives... there will be battles and fight scenes, but not on epic proportions like the other X-Men films. It will set up for the next X-Men series of sequels.
hopefully Arad's statement about these films will come true- I'd love to see the Rogue movie be made, for the fact that Rogue will probably get her real powers, and Gambit and Jubilee are scheduled to co-star in it. Awesome if it comes true.