It's (almost) impossible to do it in UBB because it uses cache, so you can't make a forum page specific for that user.
Actually, it is possible: if you add a new way/change the current way UBB stores topic information for forum page to have the replier(s) member #(s) in there, then in ubb_get_topic.cgi and ultimatebb.php add a cookie which has a hash of all topic #s and "1" if the user has replied and "0" if not.... but it's very difficult and will slow down your board