alwayscold- Tell your husband to install molly bolts with the door in the closed position (meaning not in the pocket). Once the backsides of the molly bolts have been compressed, they will stay in position and will not be anywhere close to the surface of the sliding door. Then all he has to do is remove the bolts and take them to the hardware store so he can buy short ones -- probably 3/4" or so --with the same thread. The original longer bolts are only necessary for installation of the part that is inserted on the wall; the substitute shorter bolts will have exactly the same holding power. If he is still reluctant, I don't know what to say...I've done this a number of times with no damage to the pocket door. You can easily determine how much room you have to play with in picking a bolt length by figuring out the distance from the surface of the sheetrock to the distance of the installed door and using something that is 1/4" shorter as a margin of safety. Alternatively, I've installed 1/2"-3/4" thick wood blocking on the backside of the sheetrock in a remodel situation. You install the pocket door frame, you install the sheetrock on the side where you want to hang the towel rack, and, before you hang the sheetrock for the other side, you insert the wood blocking and have one person hold it in place and another who screws through the sheetrock and into the wood to bring it tight against the backside of the sheetrock. Once you've done that, you can attach the towel brackets with short screws into the concealed wood blocking. Then you close up the other side of the wall.

Jamie Ludwig....55 inches between edge door and wall, whole wall 86 long, it is a large space. Thanks for advice about placement; that is my biggest dilemma(where on large wall to center)!

No, we don't.

You will still need substantial room for the plumbing P trap, and other bits. Without a faucet, the idea seems rather questionable and prone to contamination and smells from the organic matter in coffee and other beverages.