Very timely, as soon as I posted about a medallion, I checked my mail and saw the pre-order campaign for Angel. Not the same thing, obviously, but still in the direction I am heading.
I've always wanted to get a "fitness bracelet", because I think tracking data on myself lets me do better science. But the closed, proprietary nature of everything till now has put me off. I figured I would eventually just cave in and use one, because it seemed unlikely that it would change, since it is such a niche market. However, I think the economics of prototyping has changed a lot in the last few years, and the Angel may be the open device I am looking for.
I haven't gotten the exact info on what they mean by "open", but on their developers page they write, "Use our SDK and open-source code templates to develop smartphone apps." So one can hope.