I've read it all the way through, a couple of times even, and still have to agree with the posters who hold that there is no reason to concern yourself with stocking ammo for other people especially in calibers you don't personally own. If I had any type of firearm and for whatever reason (living in the military dorms or in someone elses household) didn't have any ammunition, if I drove "halfway across the country", at some point I am sure I would have been in or nearby a Wamart and thus would have had the opportunity to purchase some. If, for whatever reason, I didn't feel the need to, then it would be no one's fault but my own and I personally wouldn't accept a handout from a new neighbor just on the basis that I wouldn't assume being placed in that position of need. I would hop my rear end into my vehicle and take care of my own situation instead of relying on someone else. First off, you would never have known that I didn't have ammunition as that knowledge is certainly NOT something that I would mention in casual conversation with someone that I had only known a short period of time.
If you're stocking it for trading purposes, more power to you, it's just unneeded weight and space that would have been better served taking care of your own needs. Conceivably you could go the rest of your life without ever running into someone needing that particular caliber.
All my friends shoot the same calibers I do with the exception that I don't use .223, we all base our armories on 9mm, .40, 7.62x39, .22 and .223.