The first was easy; cuffs. Nice soft velcro cuffs, with one of the little metal clips to attach them. Cuffs are very efficient bondage; less bulky than ropes, lightweight, and quick.
The second wasn't too hard either: Nipple clamps, because I like them, and they are really small, especially the little tweezer kind that tightens when you slide a ring over the two prongs, perhaps connected with a chain. If those don't pack enough bite, clothespins are just a little bulkier, but the tweezers win for size and weight for this "travel set"
Number 3... so many choices. You can do a lot with a single paraffin candle, but not in a hotel room unless you want to risk extra charges. A Wartenberg pinwheel is small and versatile, so that might be a good choice. A vibrator, perhaps a vibrating egg, can be pretty small. I decided to splurge, though, and go with a suede flogger, despite the size... it can fit along one of the inside edges of a suitcase and hopefully not require me to have to leave behind any clothes. The one I have has a rubber handle, and with a condom is a very nice insertable. I'm willing to do without the vibration in order to have the rest of what a flogger brings to the ... table? Perhaps bent over the desk, or the bed?
Of course in a novel, whatever the hero needs in a scene can always be retroactively packed in his suitcase with some quick editing, but we have to deal with time in a linear fashion in real life, alas. Anyone else have any travel toy favorites? What would you pack, or have your partner pack?