Hi Cristian
I take a look on the links that you show me, there is a nice project but no one did a reverse proxy cache, only a reverse proxy. I search in the internet and i belive that the best method to do this is use a asynchronous HTTP handler. I make some test with IIS7 new cache features and i belive that i can make something very nice with it.
If someone have any ideia about it and want to share it with me, please post here. I will update this topic with new about my progression on this project.