I've been restricted with what I've done with my PT as I broke the screen on my Nexus 7 shortly after taking delivery of my watch .

I did notice this on Kickstarter:
https://www.kickstarter.com/projects...-and-modular-p

There's a $59 option which gives you GPS and NFC support. The whole project looks really interesting, with so many possibilities, but I don't really have the knowhow, or the time to get something done with it.