To answer my own question: yes! http://old.wikipedia.com/ (but you have to put the "old" in after every click; it's still configured to provide every link with the "www" in the URL. Lee, can you change that?)
No, but Jimbo can. Jimbo, could you (a) set up DNS so that "old.wikipedia.com" points to ross, and (b) change the wikiLocalSettings.php file in the old system to put "old." into the internal links?
The fact that "wikipedia.com" still points to ross is a problem for some people as well I understand, but I'm reluctant to ask you to change that specifically, since that will affect many other things