Stream iTunes TV shows to iPad?
You could start the download of the TV show on the iPad and then start watching it after a few minutes (depending in your connection speed) once its buffered enough.
To do this start the download in the iTunes app and the switch to the videos app and you can start watching, as it downloads it will fill in the time slider bar in white. 
Then delete it after you've watched it. This is effectively streaming. 

Hopefully the rumoured upcoming iTunes revamp, will include more natural streaming. It's likely though that there is no traditional streaming because of licensing issues.