That's an excellent idea and in fact something I've had on the drawing board on a general level for some time now; so far cross-site logins, visitor accounts and cross-site content search and integration have seen very little practical application, but I believe they are an integral part of the interconnected nature of the emerging cyberspace, both within software platforms and cross-platform.
thx CodeSatori and for your comment, cross site content search sounds also damn good, that opens my mind, I will think about it :) I also had the idea last week of chancing the color of all links sidewide with the push of a button or triggered through service loads from the server depending on the daemons/cpu/what else, due to maintaince preparation, virus warnings, heavy loads or shuting down, or restarting services with green-yellow-red colors and than changing them back to the css template colors, see more if the services are active again, up and running...