I recently purchased 2 LED sealed 18W headlight units off ebay that fit into the bigfoot's headlight opening almost perfectly. The lights were easy to wire using a couple of quick splice connectors. I drilled a small hole just below the opening to install a mounting screw so I could used the included mounting bracket. The argo headlight cover hides the mounting screw so you can't see it. Overall it looks pretty good and provides a lot more light output than the led bulbs or stock bulbs I've been using.

My original ideal was to use the argo rubber headlight gasket that later argos use to provide a nice seal around the LED headlight but the gasket is a bit too big so I still have to come up with some type of gasket material. There's perhaps an 1/8" gap around the light which I"d like to seal up.

The lights I"m using are the flood pattern versions and they put out quite a bit of light. The included pic shows the 18W LED headlight compared to a SMD 13W LED bulb I have installed in the other headlight. The new headlight is significanlty brighter... and is providing all the illumination. Compared to the stock bulbs the 18W is much better as well although I didn't include a comparison shot.

Here's where I got them on ebay 2X18W LED Flood Beam Epistar LED Work Light Offroad Lamp Car Truck Boat SUV 4WD | eBay