Futhermore, if I ever change the CSS or anything else just a little bit, then the video isn't matching the site anymore.

I would like a video that shows a 'cartoon' version of the main features. (Edit: by cartoon I mean simplified.)

Also, being French Canadian, I have a big accent that can be off-putting; a more traditional American or British voice would be great.

Is there a firm offering to make such videos? Any good/bad experiences with them?

Thank you very much in advance!