Wow, guys, not everyone can give their horses 24/7 turnout. I'd love for my horse to have 24/7 turnout, but in my area it seems like the only places that offer pasture board are the low end places- no individual feeding, no arena, etc.
OP, the only nasty tasting stuff I've had any luck with is a supplement called Cough Free. I had to give it to my horse last year for a seasonal cough; it smells (and apparently tastes) awful. It was an incredible pain to get my horse to eat it, but I discovered that it was a very good deterrent to keep him from cribbing on the crossties. I just rubbed the mostly-empty bag it came in on the ropes of the crossties, he'd grab it with his mouth to try cribbing and immediately spit it out. I haven't tried putting it on other surfaces, but I bet if it were mixed into something to make it a spreadable paste it would have a similar effect (but might have to get re-applied frequently depending on what it's mixed in with and how quickly it rubs off)
I've tried collars, and I found the Dare Cribbing Collar
to be the best for him and easiest for the barn staff to put on and off, but after several months that, too, starting rubbing. I've left it off for a while now and really only use it when I take him off property (I never know how other BO's are going to feel about a haul-in cribbing on their property)
Honestly, if he's not having any health problems from cribbing and it's just the annoyance of the sound, I'd just let him keep doing it in his stall.