trouble syncing Low res iTunes downloads (Video)

Well here is my situation.
I currently have my Mac Mini hooked up to my 55" TV. It serves as my monitor for playing games, surfing the net, watching Netflix, etc., etc.
I have recently decided that since the Mini will output full DTS surround sound via the HDMI connection that i wanted to stop purchasing Blu ray discs and just buy the movie on iTunes. This would allow me to sync the movies to my iPad or iPods and watch on the big screen without having to find the Blu ray with digital copy (which is more expensive by the way).
My problem is when i download the HD version of a movie, like Iron man this morning, it downloads the HD and SD version. However only the HD version is listed in movies under iTunes and its 3.6 Gb. I found the SD version, at 1.6GB, but i cant seem to add that to itunes library for syncing to the iPad. My iPad has 38Gb music, 9Gb apps, and 4Gb, photos on it which doesn't leave a lot of room for movies at 3+Gb a piece. Any ideas aside from renaming the SD version Iron Man SD and the other Iron Man HD???

thanks