The images here give a few examples of runners that I have found for clients in the past.
It is commonly believed that Oriental runners are easy to find but in fact they are one of the most difficult. Unlike a rug for a lounge there is often little leeway in width so the difference between maximum and minimum width may only be 5cm hence reducing choice. Runners also tend to made in approximate metre lengths but corridors don't.
As a runner increases in length there is a greater chance of tension problems so causing the width to be narrower at one end. The narrower and coarser (fewer knots per inch) the harder it is. This is one of the reasons why there are so few runners of over 6 metres. For very long corridors one solution is to provide two runners that compliment each other.The size required will determine what styles of runner are possible.
Because of the difficulties of having just the right runner you might need my approach is to search for runners for clients.
If you would like to discuss your requirements for a runner do give me a call.