I know this thread about conduit rope sleeves is old, but I've only just noticed it (I've not been keeping up with the forums, I must admit).

I want to remind everyone that you can buy the conduit from McMaster-Carr (PN: 8069K13 and called "Ultra-Flex" within the "Liquid Tight Flexible _meta_l Conduit" category) very inexpensively (currently $1.93/foot). When your sleeve starts to show some wear, simply remove the endcaps and screw them into a new length of conduit. I like to put some colored gaffers tape around the lip of the endcap so that the black sleeves are more visible and I can see how they are positioned. I have sleeves in a few lengths and use a different color tape for each length so that I can grab what I want more easily.

For those who'd like to get a hold of some endcaps, I've listed here (on my terribly out-of-date Flickr site) where you can get the endcaps, too.