To combine a couple of the ideas here, how about a Hijack api which allows a user app to publish an arbitary entry in /proc with certain information that might be usable to other user apps. Like gpsapp could tell Hijack to create a /proc/gps which would contain the current coordinates and whatever other information might be relative to apps that might want that info. Sort of like /proc/empeg_notify, except that user apps can control the contents of the /proc entries.

Useful? No?