Have you tried the Pinch Method?

The Pinch Method is a method you can use when you knit cables without a cable needle. 

To try this method take the stitches that would normally go on a cable needle and pinch them together with your fingers when you take them off the needle. 
Now hold those stitches to the front or back according to the pattern as you work the stitches from the regular needle.  Replace the pinched to the left needle, then knit them off. 
Start with a 2 stitch cable and work up to a four stitch cable. 
I know it sounds scary, but give it a try, you might like it.

This tip is from the book Power Cables by Lily Chin.  This book not only teaches you about cables and how they form and how to do reversible cables, it also has good picture support.  From cable casting on to short rows and mattress stitch.