Ok, I had a buddy with access to a lot of computer-controlled milling equipment design and produce these adapter rings. They will allow you to mount a 4" round LED sealed truck/trailer lamp into a round style M-series lamp housing. The look is similar to the Gama Goat taillamps, with the face of the adapter meeting the LED lens nearly-flush for a "one-piece" original look. The adapters are designed to accommodate a wide range of 4" round lamps originally designed for mounting in a rubber grommet. The design utilizes a stock-type flat o-ring to seal the backside of the lamp assembly into the lamp housing, maintaining a 100% waterproof assembly. These are basically a bolt-on other than certain brands of LED lamps may require minor grinding of the ridges on the inside of the housing for clearance.
The rings can also be used to mount the aforementioned LED assemblies into a flat panel without the use of the M-series lamp housings, producing a semi-flush fit with a rugged appearance. Perfect for Jeeps and other trail rigs.
These photos are of unfinished pre-production samples and the camera has made the tool marks visible, although they are actually perfectly smooth to the touch. The production units will be offered powder-coated in a few colors (including OD semi), polished or unfinished.
For more and larger pictures: http://homepage.mac.com/m715/led_tai...taillamps.html
Let me know if you would be interested in a set. Warning: considering these are milled from a 1" thick solid aluminum plate, they will not be cheap. However, I do plan to offer them to Zone members for darn-near production cost (which is still being determined).