The core idea of what you discuss here was put forward as a project a while ago in either the Ideas or the Projects forum. Supposedly if it got as far as beginning implementation, it would go into Projects. I am not sure if it got very far: for interest you might care to scan back through both forums. Since Mark Lord is into GeoCaching in a big way (hi, Mark!) and is also the author of the HiJack kernel, it might be worth getting his opinion.