Thanks for the info. I might just try a custom nut with locktite. It seems to me that the larger diameter stock nut would keep the sprocket a little more true, and that a shorter nut would also tend to wobble less. It sounds like the custom nut should be around $80. Since I'm already getting custom axle adjusters made I might as well add a little more work.
I'm not sure if I want to run an open sprocket cover or not, I was actually thinking about spraying a little bed liner inside my sprocket cover to replace the huge sound/vibration damper that was on it.