The easiest way I can see of doing this would be to create a cookie for you, copy it outside of the normal folder and rename it to something like
ga@archery-interchange.txt then create a cookie for mrs GA and move it outside of the normal folder, and call it
mga@archery-interchange.txt now you create a batch file to copy the ga cookie into the correct place, renaming it to whatever its called in the first place and then launch your browser program to connect to
www.archery-interchange.com. create a shortcut to this and call the shortcut ga's
aiuk. repeat for mrs ga's cookie.
This method is trivial on a local machine compared to the work Dave would need to put in to do it serverside, and its certainly do-able - whether you want the hassle or not is another question. I know that multiple profiles can messup personal email accounts pretty well unless its web based mail but thats the only downside i know of- switching users can be as simple as windowskey+L