Rename non-posting-users

[symptome]

I don't want to delete non-posting-users. But I want their names to be available for new users. Is there a possibility to run something, which searches for users ...
- that didn't post something
- that are registered since x months/years

.. and to generate a number behind their name (counting from 1 to 999)

Example:
If there is a user "muster" and there already exists a user muster1 and muster2 then "muster" will be renamed to "muster3".

Thanks!

[symptome]

Do you don't have those problems with larger boards??

[Videx]

I've seen mods that will automatically prune inactive users. But not one that will simply rename them to add sequential numbers behind their name.