I would search around for non-splite wire loom - like this:

http://cableorganizer.com/wire-loom/...-wire-loom.htm

It comes in various diameters and colors.

If you can't find the right size/color in non-split, you can probably still use the split. It comes in as small as 1/4". More examples:

http://www.electriduct.com/Colored-S...oot_p_278.html

.