Screencasting in 1080p from a retina display without scaling, possible or not?

I want to make some tutorials in 1080p on my MacBook Pro with retina display. Is there a way to record the screen "natively" in 1920x1080? I don't care if it would look scaled and blury at the time I'm recording it. Also, I wouldn't mind if I had black bars up and down (due to the different ratio). I just want to have a sharp 1080p video as the final result (a video that will be as sharp on YouTube, when it's switched to 1080p playback).

Has anyone tried it? Any suggestions, preferably experiences? Thanx...

After much searching and toying with various programs I finally found one that did exactly what I wanted.

http://www.madrau.com/

Now I have this fancy menu that I can use to quickly change my screen resolution.

I record my screen at 1280 x 720 HiDPi (720p). It puts black bars on the top and bottom of my screen, but for recording purposes that's totally fine. You can also record at 1920 x 1080 if you need 1080p, but I find that text gets really tiny at that resolution; with 720p I only need to zoom my text editor in slightly.