[BirdOPrey5]

This would be a pretty involved mod but the user of custom profile fields simplifies it somewhat. The fact you want a drop down box wold mean adding a new field to the post table in the database, which is a line I never crossed for mods I've made, but in theory not that hard.

But of course my mind is programmed to look for alternatives to database alteration at any cost so let me bring this possibility up...

Your users have 4 different "names..." If these names are stores in a custom profile field what if each user had to start (or end) each post they make with 1 of the 4 names.

Then a php plugin could read the post, extract which of the 4 usernames it matches, and set a variable from 1 to 4.

Then in the postbit template you'd have all your possible postbuts enclosed in IF conditions...

<if condition="$postbittype == 1">
postbit 1 here
</if>

<if condition="$postbittype == 2">
postbit 1 here
</if>

<if condition="$postbittype == 3">
postbit 1 here
</if>

<if condition="$postbittype == 4">
postbit 1 here
</if>

I'm not offering to make the mod because it would be of very limited use, just trying to give some ideas since you said you were open to a point in the right direction.