There is a mod you can do to your flasher relay located on your steering column. It requires some soldering. Gen Right sells a LED flasher relay if you're more in to the plug and play type of modification. I think it's about 30 bucks.
Is the relay flashing fast a general problem or a jeep specific issue? I put LEDs on the back of my Landcruiser and had no problems. Maybe I just got lucky?