I've never used an honest to bob cable needle, I just use bamboo DPNs that are close to the same size as the needles I'm using. No fuss, no muss, just slip on, knit off.
I did read somewhere that a lady got in a bind and used a golf tee to hold the stitches she was cabling. But it seems like you'd have to put them back on the LH needle before you could knit them, and ... well that just seems like time you don't need to spend. Plus a golf tee is only going to work up to about a US 8 or so, so if you're using needles much bigger than that it won't work. Or... much smaller either I suppose.