Originally posted by RioRico To work further away, a 135mm lens, and either three sets of tubes or a cheap bellows, will do the trick.
Just to add to that, another good, cheap route is to slap a 50mm or shorter prime on the end of your 135mm, reversed. You can get some pretty crazy magnification this way. The other day I experimented with this by reversing a 28mm on the end of my 135mm, and the magnification was just shy of 5:1 (but the DoF was about as thick as a sheet of paper at apertures where you could see much). The only extension with this was caused by the required step down rings and reversal ring between the lenses.
Still, a 50mm on the end of a 135mm is a more moderate approach that works quite well.