I purchased a set of the Best Dual Sport Bikes Dead Ends anti-vibration bar ends for my 2004 KX 250. I finally got around to riding the bike today and I was floored by the difference they made in the vibration levels. My bike went from hand numbing in a matter of minutes to almost no vibration. They are fairly easy to install and look similar to the bar ends on dual sport bikes. Here's the website:
http://bestdualsportbikes.com/dead-ends-anti-vibration/ 
One tip I can pass along is that the tap you use to install the bar end is too large for the tap handles that you can buy at Lowe's and Home Depot. It will fit in the end of a 3/8" extension. I used a 3/8" to 1/4" adapater, attached to a 1/4" extension that I installed in my tap handle from Sears (see below). Worked like a champ!
