How to get super macro on Nikon?

I know Canon has a super macro lens (5:1). Is there an adapter I can get to make it fit on Nikon camera, since Nikon doesn't have any super macro lenses? The only thing I've heard is to reverse the lens and attach another lens, but this leaves virtually no depth of field(2-3mm). So what's the best way to get super macro with a Nikon?

I use extension tubes or a bellows if I want to shoot larger than life macro photos with my Nikon's

If you don't have the lens yet you can get good ones that fit your Nikon camera made by sigma for a lower cost.

Here is a link to the US sigma site, I took it as far as Nikon macro lenses for your use. They work just as well and cost way less then Nikon and canon lenses.

If you already have the lens you can buy the converter ring.

Probably your best choice would be extension tubes.
http://www.kenkotokinausa.com/products/kenko/slrc-04.html

If you choose to try bellows instead of extension tubes you'll have to buy used.
http://www.camera-wiki.org/wiki/Nikon_Bellows

If you use a lens reversal ring, you could use a lens with a manual aperture ring, so you can control the aperture. Like one of these: http://kenrockwell.com/...-f14-s.htm If you stop down to about f/8 or f/16 it will help reduce the narrow depth of field problem. Another area you can look into is to use focus stacking to combine multiple exposures.