The only time I had issues with a hose rubbing the back of my neck was on one incredibly long 5 day trip on a liveaboard. It was an incredibly long week, as pretty fish diving in tropical without a hood allowed the braided cover on the hose to rub my neck raw after about the 3rd dive on day 1. I went back to rubber as soon as that trip was over. I have a 5' miflex hose really cheap if you want it...
I used to live in SD, and I hear you on the dive travel thing, but it's all relative. My technical diving buddy and I used to fly to do wreck diving in the great lakes - two sets of regulators, can light, back up lights, dry suit, etc.
Now that I live in NC, my wife normally drive to Florida to cave dive, but we also fly to Mexico every couple years to cave dive. For each of us it's two regs (with 5' hoses on each), two computers, can light, two back up lights, side mount helmet, BC, XL jet fins, 400' primary reel and a half dozen finger spools, wet notes, wetsuit and boots - and it all fits in a second generation Dive Caddy, which in turn fits in the over head bin, with the small detachable turtle bag becoming your personal bag.
When we do something like go to Bermuda or fly to Key West to get on a live aboard and we just have our single tank pretty fish kit, the Dive Caddy is practically empty. Given that I use a back plate and 30 pound wing, I also use a 7' hose as the primary, and tuck the excess under the waist strap.
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I started diving CCR a couple years ago and I carry the bailout reg on a 5' hose routed to a bungee necklace. It's easy for me to access if I need to bailout, and if you rig the bungee short enough you can access it hands free. It also serves as a donor second stage for a team mate in mixed CCR / Open Circuit diving. But I regard it as a necessary evil. In 32 years of diving, I've donated gas 3 times. 1 of the three was on a technical dive where we knew it was going to happen following a failure so it was all very controlled. The other two were on open water dives and both times the out of air diver was a stranger, you was both out of gas and separated from his or her buddy. Both those gas shares are better described as muggings, as the divers were in a near panic and grabbed the reg right out of my mouth.
The golden triangle stuff sounds great but in reality a stressed and out of air diver is going to just grab the reg they see making bubbles, with no warning, rather than calmly swimming up, giving you an out of air signal and looking for your octo. If you see them coming and you're on the long hose primary, you can just hand it to them, and then go to your bungee back up. If you don't see them coming, you're going to get it ripped out of your mouth and you'll appreciate a bungee back up, as opposed to having to locate your own octo and un-clip it. Murphy's law dictates that you'll get mugged at the end of a full exhalation.
The good news is that since you donated/got mugged for the long hose primary, you're all sorted out and ready to ascend. Plus, with the length available with a 5, 6 or 7 foot hose, the OOA diver will not feel like the hose is about to be pulled out of his or her mouth and they'll be more likely to calm down.
If however you're breathing the short hose reg, and you get mugged for it, you've now got the OOA diver on the short hose, and he or she is going to feel like it's on the verge of getting pulled out of his or her mouth. That does not inspire confidence in the diver and just increases the panic. And you've got to sort this mess out before you start your ascent.
I'm a huge fan of breathing and donating the primary, as it actually works in the real world, as opposed to the totally artificial crap that gets taught by way to many OW instructors.
