Navigator playback options?

[spyderheart]

I really love the Little navigator panel playback function to have a tiny lightweight and realtime preview of the animation looping all the time in the corner so you can keep the overall sequence in mind as you go into detail.

Is there some way to set some limits on the playback range though?
On a long sequence it would be great to be able to only loop between Mark In and Mark Out for example, or even an easy In -> Out setting that only applies to the navigator playback. This way you can narrow the focus a bit so you don't wait for it to loop around until you see the part you're interested in.

Another potentially nice addition would be a playback quality option. This could allow for larger and previews when resources allow it.