If you don't feel like shelling out the cash, you could try hanging kettlebells (DBs, or plates would work too, although KBs work best) from a bands or something like Spud straps. You will get some serious stabilization work in. I'm not going to say it's the same as using the Tsunami one because I've never used one and two because w/Tsunami, the bar itself is unstable where as what I'm talking about the bar remains stiff and moves more from side to side with the KBs swinging around. With the hanging KBs on the straight bar, the faster you move the bar the more you're going to get banged around by the swinging. Plenty of vids around if you want to see what I'm talking about.