It's possible, but I have yet to find any anything online from people who have done it. There have been several posting on other web forums asking how to do it. I have yet to see someone post how it's done. The problem is that the period (.) in mod_rewrite gets treated as another variable. You may be able to add another variable at the end of your rewrite command for the user.php file and see if it works then. This, however, would assume that all users have periods in their usernames, however.