I like using armored steel tubing.
The spring wrapping protects the steel line from abrasion, and also makes bending it much easier, as the spring stops the tubing from kinking.
You can buy this tubing in 6" to 72" lengths from Papco-Paulin ... and I am sure many other manufacturers as well.
Here is a link to a PDF catalog
that contains many different products ... including some nylon tubing solutions.
also offers a reusable spring type bending tool.