QR code key exchange is convenient, but I did not plan phone support.
What I REALLY want is an app that builds a big bank of nonces between you and your peers over short range radio or QR codes and then lets you use a 1-time pad.
Ultimately, I'm only offering criticism because I have spent a lot of time working on exactly this problem, but I am not in a position to actually implement it. This is awesome and you should be proud of it.
However, there is also another way, which is already implemented and I am currently writing the how-to on my blog site, and that is using "trusted users". Basically, instead of 2 users trying to find each other on the DHT, they can just export their profiles in the "Profile" section. That prompts them to create a shared secret and exports a ".kiyeovo" file. You send that file to the other party, they click on the "+" in the sidebar header ->"import trusted user", select the ".kiyeovo" file and voila!
I know it's not nearly as convenient as what you're describing, but it's just a more "trustable" way of creating a contact which is also not that inconvenient.