I'll second that ds650ratrider. My pictures show one installed on my ride. I get lots of comments on it and have had
it on for over a year without problem. Couldn't keep the OEM or even the LED replacement bulbs in with paddle tires
on, the vibration ate them up.

 

I put an LED in a long long time ago, it was good for a few months, but eventually even it destroyed itself in the vibes, it just shook it apart.

I then realized I was tightening the screws too tight, compressing the rubber grommets too much so they couldn't do their job.

I have now had a regular 1157 bulb in there for over a year and many many monster dune rides with haulers on and it still works, just from loosening the bolts a bit and allowing it to float a little better in the grommets.

 

DuneRider650 I did the exact same thing you did and it was the easiest and cheapest fix I've ever experienced on my DS.
The one trx450r tail light that ds650ratrider put up a link to looks like it would work also with a little imagination and fab work.

 

The trx450r light I posted is what I want. I got one of those truck LED lights snotted onto the back of my bike. I looked over my friends trx450r pretty closely and it looks easy to install. One of these days it'll be more important to me and I'll get one.

--

 

Yeh, my first night ride the damn thing burned out! Brand new bike, whats up with that? Then my dealer wanted me to bring the quad in to warranty the bulb instead of just trading me bulbs or I could buy a bulb from them for $7. Bought two from the local autoparts dealer for under $2 instead - pi$$ed me off if you now what I mean.