This might be difficult.Even though the concept of Color is simple, it seems like they have some complex stuff going on behind the scenes.I don't think you can copy it in a weekend
How about a reverse color -- in which you DO NOT own (meaning get associated with) any of the pics you take -- they ONLY get plotted to and left on a map using simpleGEO.
Basically, you pull out your camera, snap a pic and it gets uploaded and displayed at is geoloc, and removed from your phone - then all you see is anon pics left where they weree taken.
One data point that would be of use/interest would be the direction of the camera, and a timestamp.
so, since they believe GPS is a non-starter -- lets do this with GPS... dupe the interface and basic functionality