A title for "lurkers"
 

The current title setup is based on the number of posts made.

Is it possible to create one whereby if a user has made x number of visits within a certain timeframe (y) and not made any posts their title is changed to that of "lurker" ?

X and Y would need to be admin configurable.

This could be extended to incorporate inactive users to be marked as inactive after x days without visiting the fourm.

Yep.

Use different usergroups with promotions where the junior usergroup forces a newbie title and the more senior one allows a custom title.

OK but that method would not allow for changing the title based on the number of visits over the last 30 days for instance