are you asking that you want to use another absolute path outside your server for a page?
I don't use base href anymore (I setup absolute paths via my htaccess file) so not sure if it would affect your link if you added an absolute path there.
I do know however it does work correctly via htaccess.
For example I have all of my site links to preface with http://www.atseadesign. The URL part of my image or link then has /directory/file.
But in other areas of my site I use an absolute path without any problems. i.e. http://twitter.com/blahblah
I guess the best way to see if it works is throw it in there and try it.