A Google AdWords Help thread reports a bug with Google TV Ads where some advertisers might not be able to get it through their AdWords account.
Most AdWords accounts have the ability to click on a "Create TV Campaign" at the bottom of the campaigns page. But not all.
Vincent from the Google AdWords team confirmed the bug. He said:
I'm also sorry for this. It's actually due to a issue on our end where not all accounts have access to TV ads.One workaround is to sign up for a new account through the link at http://www.google.com/tvads. This will direct you to a sign-up flow that will guarantee that you have TV ads enabled in your account.
We do have a team monitoring the form you filled out but 3 weeks sounds abnormally long. I'll escalate this to our TV team and make sure they're following up in a more timely manner.
What should you see? Here is a screen shot from my account:
So if you are having problems, post in the thread and you might get help. If not, use the google.com/tvads method and you can start TV ads today.
Forum discussion at Google AdWords Help.