Okay, you had me; then you lost me. IMHO, a glass door only makes sense to keep out the weather and the birds. Interior doors are for controlling the views (maybe you're thinking frosted glass?). If you're thinking of a glass door inside, then I suggest you think long and hard whether you need a door or not; leaning toward not. If you need to keep out small children and other critters (glass = fingerprints!!), then a gate will do nicely.

There are hanging door tracks in a contemporary style ($$) that could look right with a glass door, but I haven't seen many farm houses with what I would call a contemporary interior...