If you're in the same boat as me (and I sure hope you are, or this is a useless post), a script from the venerable Doug (you know, AppleScripts for iTunes Doug?) called Set Video Kind of Selected can bring some automation to this process. In fact, as you can see, in allows you to edit not only the Video Kind, but the Show Name, Season Number and the starting episode number of the batch you've selected. This is a killer script for those of you who have some major iTunes video library cleanup work to do.
As usual, this script is provided free, but Doug solicits donations for all the rocking work he does with his now over 400-strong library of iTunes AppleScript.