Locational Context Change

I travel into and back from University every day and am thus constantly changing the networking settings on my PowerBook due to the different networks I'm using at home, university (VPN stylee) and having to switch wireless networking off for the train journeys (saving battery).

What I would like is some sort of system wide change dependant upon the network location I'm in.

For example, when in a networked area I always run a few widgets to pull things off the web, like flickrframe and a wikipedia widget. What would be nice is when I switch to a non networked location, these widgets would disappear off my dashboard until I get back onto a network.

Another issue I have is with Safari, whenever I launch it I am always taken to this site, which is fair enough if I'm on a network. But wouldn't it be better to take me to a different location when there's no network available (such as http://localhost), I do a lot of work on the train and it annoys the hell out of me when I launch Safari to be presented with a page telling me I'm not connected to the Internet - no shit, that's why I changed the location in the first place!

I'm sure they're are other arguments for and against doing this, but it would be nice to have something available to do it for you.
- Chris