In other words what looks best regarding it's overall length relative to it's height.

Whatever looks good. 3:1 and 4:1 look ok, too. First two are 3:1, last is 4:1.

<img src="http://panekfamily.smugmug.com/photos/39086609-M.jpg">

<img src="http://panekfamily.smugmug.com/photos/39091471-M.jpg">

<img src="http://panekfamily.smugmug.com/photos/39086603-M.jpg">

There are 2:1 cameras sold as "panoramic" but I've heard people say true panoramic starts at 3:1. The beast pictured has a frame size of 56x168mm. I actually like 2:1 better somehow.

<img src="http://www.robertwhite.co.uk/Pictures/Fuji%20617.jpg">

<img src="http://upload.wikimedia.org/wikipedia/en/thumb/5/5f/Fuji_617_back.png/250px-Fuji_617_back.png">

<center><img src="http://pictureposter.audiworld.com/80402/beach_05small.jpg"></center><p>

this one :)

<img src="http://pdxa4.smugmug.com/photos/50628593-O.jpg">