How do I disable SMS when traveling internationally?

Details.

• Running "IOS 8"
• "iPhone 6"
• I am traveling in Hong Kong
• iMessage is enabled so that when I reach wifi I can send/receive messages
• Send as SMS is disabled
• Cellular Data is disabled
• Enable LTE is disabled
• I'm using an offline GPS app called Gaia GPS so I don't have "Airplane Mode" enabled.

Challenges

• My friends are still sending me SMS messages from the USA
• Why I am still receiving these SMS messages
• Why I am getting charged for these messages
• How can I get GPS reception without receiving SMS messages?

Obviously Not acceptable solutions

• Reset my phone (seriously?)
• Submit feedback to Apple (you really think they'll make a fork in their build to accommodate people who have an issue with international data?)
• Disable Cellular (there is no option to disable cellular in the phone menu anymore, the only option is by removing my AT&T sim card)
• Remove my sim card (Let me get this straight, you want me to remove my tiny as all **** nano sim card that would make it significantly easier to lose and would eventually need to put it back into the sim slot when I get back to the USA, you crazy)
• Tell people to stop sending me SMS (I have a lot of friends and a lot of them forget that I'm traveling and they will send messages like happy birthday, or how are you doing, or let's hang out -- Telling 100+ people to use facebook message or get an iphone isn't really a scalable choice, work around, or even reasonable decision)
• Use Airplane mode (I already told you, I'm using an offline GPS App and need GPS to work on my phone, and no, I am not carrying a separate external bluetooth GPS/GLONASS receiver)
• Use a local sim (AT&T locks phones under contract, I have a two year contracted started in Feb)
• Pay to have your phone unlocked (And void my applecare warranty? you crazy)
• Pay to have your phone unlocked by AT&T (that's a $295 dollar charge, I already have a second phone for local use)
• Turn off your phone (Like I said, I still use imessage, and I still use an offline GPS)
• Use your second phone as a primary phone (The second phone is voice only, an 8gb capacity android with froyo)
• Buy another iphone (Seriously, this is not the thread for you)
• Update my phone (Unless the update specifically states that there's the ability to disable cellular messaging, I'm not upgrading. I'm not risking the chance of bricking my phone and having to waste time going to the Apple Store, schedule a genius, and replacing my phone.)
• Installing a MDM Profile deployed from Mac OS X Server, JAMF Casper, Mobile Iron, Meraki which offers granular control and disables any function I want (You want me, or everyone else with this problem, to purchase enterprise software, write a mobile device profile which disables the mdm, and then deploy it on a single device -- you and I probably need to have a talk about customer service and customer impact and what's acceptable and what's not)

I hope you all had fun reading this. 🙂 I sure as heck had fun writing it. The TL;DR is that Apple doesn't seem to have an ability to disable cellular radio anymore to prevent it from accepting calls because they wanted to streamline the whole process and included it into Airplane mode. Eventually Apple will streamline it to the point where you only have one button which is the touch screen and if you want to send messages you'd type in morse code or something. If someone knows how to disable calls and sms and anything else that would charge me money but still allow me to use the GPS receiver in my phone, that would be great. Thanks!