I have the exact same problem. It started about 3 wks ago. I stopped driving the car since I was too busy with the holidays etc. I have about 300km's on my LS400.
At first I thought I had a badly bent rim or the wheel nuts became lose. I did the TRAC fuse, disconnected the bat. nothing changed. Mine is only on the front. When I drive forward, the steering wheel turns to the right each time the wobble happens, if I reverse, the steering wheel goes to the left. Seems like only one of the brakes is engaging. The event happens around every 6ft, forward or reverse. Prior to looking at this forum, I thought the ABS is engaging on one wheel, due to a bad sensor or something.
I tried driving the car with the brakes engaged, still happens. Is there a way to safely disable the ABS system?