Nerf's N-Strike line aren't the only blasters receiving the battery powered treatment. Behold the Nerf Super Soaker Thunderstorm; a fully automatic water blaster. From what I can gather, it has N-Strike compatible tactical rails, runs on 4 AA batteries and comes with a water "clip", much like the way the CS series go. It can support all N-Strike stocks as well, and the clip looks like it's got a belt clip to attach to your boardies.
Electronic water blasters have never really been that fantastic for range and performance, so it'll be interesting to see if Nerf can do any better. More intel as I find out more!
There's a guy selling one on ebay, however it is out of packaging and "as is" so the asking price for $120US is a little steep.