From heat shrink tubing, automotive rear air shock sleeves to official Jagwire black housing liner, it proves there is certainly more than one way to skin a cat (great expression, don't you think?!).

I'll likely go with the Jagwire tubing just because, although the other options are clever and possibly better material, the Jagwire product is made for this application. Plus I'm pretty sure 30 meters will last me until the end of time.

Thanks to everyone who chimed in!