i saw that in drupal in the default package
it enables the writer to choose what cont he's going to write
forum post , blog post , image , file , document ... etc
i already made it for smf 2.0 awhile ago ... by modifing that mod called reason for edit i put a selection options on post.template to add acolumn near id_post that holds one number 1 or 2 or 3 ... with every post
and modified display template case 1 display something , case 2 display something different and it worked with some issues cause am not good at php
i think its major and gonna kill some old pro mods
i hope somebody intersted with the idea also to see afree version of that
good luck