It's worth noting that WotC has basically abandoned DragonLance. From what I understand the licensing agreement ended in 2007 and they don't plan on doing anything new with it. You could try contacting Sovereign Press, since they're who has the production rights to DL right now, but I'm not sure if they'd be able to publish something that's specifically 4E... (As far as I know, anyway. I might be a bit out of date.)
Either way, your idea sounds cool. I love DL, so I wouldn't mind seeing more of this.