It would be great if we could add a class like "colorbox-load" for external links and "colorbox-node" for internal links.

I guess a good question would be whether it would even work or not even if we could add those classes. Colorbox-load would load the page within an iframe which I'm guessing would work fine.

We'd also have to be able to add a snippet to the end of the URL like: ?width=720&height=1080&iframe=true

These would have to be able to be set for each individual service as well, one for them all isn't useful for items like Forward as it would show all other regions within the colorbox, hence the need for colorbox-node (Colorbox Node) in addition to just colorbox-load (Colorbox).

Any chance this is a possibility? I'd think it should be easily possible, just a little grunt work to get it integrated with each service. I looked through the module code for Print and Forward and since I'm not very familiar with Drupal coding, I wasn't able to determine how to get a class added to the link for each.