I've thought about it, but when you try thinking about the housing, cooling, etc, it was much easier to buy one.
Amazon has a whole slew out outdoor lights running AC or DC, in different wattages.
If you're thinking about a screw-in bulb type application, again, I know I could design one, but pricing out components, getting a board made and an appropriate sized heat sink while making it look half decent made it unfeasible.
Edit: btw, I bought a couple of those amazon lights and they both seem to be working well, although they're in the garage, not outdoors.
I bought couple of outdoor led lights today from Menards, they are sylvania brand and they HEAVY, I guess the heat sink makes it heavy and from what I have read the head dissipation is the most important thing for leds.
I will check out the amazon offerings, Thanks,
A halogen floodlight recently bit the dust, and the bulb is sealed in there with caulk. I'm thinking hard about a simple two-bulb fixture fitted with Cree's LED floodlights. For the amount it's used, it ought to last a long time.