"For SD (this was the tricky park), once u select TV or movies go to the right bottom where there is check box... says download HD when available.... chec that off, u should see all the titles changing to SD.... this way, u can download specific version u would like to put it in your various devices. Might be obvisou to some folks but certainly it wasn't to me. Hope this helps to anyone."
I cant seem to find this check box that you speak of.
granted it might be because my itunes is old. (10.6.1) and its being run on an old verion of OSX (10.5.8 it cant go any higher)
either way. my itunes is downloading the HD versions of shows and has stopped downloading the SD versions. everything i've read hasnt worked.