If you're looking for ideas on what/how user status could benifit/encourage users, check out these sites:
www.ddruk.com (All avs/titles are given a value. You need to earn CP {contribution point} to get them. CP is earned by each day you post something, donating money, pleasing a Mod, etc. This would mean custom avs would not be allowed, at least not to people who have low numbers of CP.)
www.bemanistyle.com (Point are earned {not too sure how}. You trade points for downloads. There may be more to this, but I'm a new member, so I haven't found out everything yet.)