Modal windows module for Drupal 7 content? I have looked at a bunch of modal window modules but they all seem to only apply to media such as images or videos.

Do any of the modal window modules (lightbox, shadowbox etc) for drupal 7 allow drupal content to be displayed within, for example blocks / webforms etc?
I've used the colorbox module for this purpose for a couple of recent D7 projects.  It works well and seems to fit your use case.  

You might also want to checkout the overlay module in D7 core, but it generally involves more effort to make it work for the non core use cases.