Someone requested the details on how I built a macro converter for the X1. My total cost was around $20. I bought the step-up and step-down rings on eBay for $2 each. I also got the Nikon UR-E8 adapter tube on eBay for $8. A tube of epoxy was $5 at Home Depot.
I already had a broken Nikkor zoom lens. Nikon wanted $200 just to look at it to see why it wouldn't focus, so I had bought a new lens and thrown this one in a drawer. I dissected it to remove the front element. I did have to dremel off a bracket, but unfortunately I don't have a photo of that.
It's incredibly simple. The quality and grind of the element you find to use in yours will affect the sharpness and how close you can focus to your subject. Mine focuses at about 4-6 inches, which is a HUGE improvement over the X1's unassisted macro focus.
Hopefully his photo will explain it all.
Home Brew Leica X1 Macro Converter by ffacker, on Flickr
L1011777 by ffacker, on Flickr