Hi Tim, Pocket doors are made from regular interior slab doors attached to an overhead track system. The longest standard tracks I have seen will accomodate a 36" door, yet I'll bet you can find a supplier of longer lengths that are cut to fit for any application. The biggest problem you will encounter is to find a door that will span the width you desire. Typically, something this large would require twin pocet doors that retract into each side wall. If you must have a single door unit, you will probably need a door shop to make a custom door for you. You may experience problems with that much weight hanging from a track, not typically designed for such a load. In older homes, that would separate a parlor from the dining room with large pocket doors, their was a metal track let into the floor and rollers placed into the bottom of these type doors. Suppliers of hardware for restoration jobs may be able to supply the track. Check the Old House Journal for listings. Good Luck.