I figured I'd search the
vBulletin docs to see how easy it is to do the things we're discussing. It looks like a flexible, easy to manage system.
User ranks (i.e. titles like evangelist):
http://www.vbulletin.com/docs/html/user_ranks_intro
User titles:
The user’s amount of activity on the board (Junior Member, Senior Member). This is usually set through the default user title ladder that will be described in this section.
The user’s relationship to the board (Administrator, Moderator). This is usually set through a usergroup-specific user title that overrides the default user title ladder.
A custom title, specified by the user; this can refer to anything the user desires. The user may not have permission to set their own user title; it is controlled by a usergroup permission.
And, here is a plugin to show display the number of posts a user has in a current forum:
http://www.vbulletin.org/forum/showthread.php?t=105490
So, technically, it can be done. However, further down in that discussion someone writes:
It adds 1 query PER post on a thread.. So if you have 10 posts per thread, it will add 10 queries per thread. And these are not small queries. It basically DOUBLED the load time per thread. This can really kill a server.
(I don't know if this is correct...)
vBulletin is written in PHP with a MySQL back end, so I'd assume it is customizable.