It looks like the rumors are all panning out, as Lizardmen are now confirmed through leaks to be the next release. There are a couple different places you can go to get these right now, either through a video at MiniWargaming TV or over on Dakka who has screen captures of the video posted up.
Games Workshop Video Teaser
MiniWargaming TV (video) go to minute 37
Dakka (images from the video above)