Creating a tag cloud from database
 

Does anyone know if a modification exists that will create a tag cloud from threads/forums held in the database at all? Some customisation would be great, along the lines of allowing the cloud to draw results from certain forums, and showing to users with certain permissions, and from only recent posts (last day/last hour, depending on how busy your forum is). I've searched quite a bit and only found one that uses the thread tagging system, which doesn't offer the functionality i'm looking for. Have I missed a mod somewhere?

PS. for those of you that don't know about tag clouds, the BBC have a great one here which collects popular words from text messages sent to radio 1 over the last few minutes.

There is the zoints tag system, that creates a cloud. But you have to enter each one manually far as i am aware, and thats about the only one i've ever seen.