Extract ClickToPlugin Links

Here's a bit of an advanced question, and answer to which I do not expect, but here it goes:

Is it possible to get the source of a webpage AFTER extension modification?

My purpose is to create a personal app that loads a webpage in Safari (well, the webkit nightly in my case), runs it through ClickToPlugin (essentially the same as ClickToFlash), extract the video tag link via grep or some other form of regex, then download it and place it in a location from which I can load it on my iPad over the internet. I already have the entire implementation in my head, the one obstacle is getting that link. Any ideas?

I know how to get the source of a webpage via Applescript, but that doesn't take into account any extension modification, hence my dilemma.

EDIT: It's possible I could customize the plugin's source to make extraction easier, but I'm not too familiar with javascript.