Yeah, I can do tomahawks just fine. It might help to practice with a full-size frisbee first - they tend to do it easier. You definitely do have to release it nearly "flat" to the ground though, vs perpendicular to it, or you're right, it'll just turn into a roller. Start the throw with the disc up and down, and end the throw with the disc flat, upside down. If that makes sense...
That does make sense... Hrm. I have some ultimate discs that I can try that with. I'll see how it goes!
A friend of mine has the most acrobatic tomahawks; they're a sight to see. He releases at some angle, I have no idea what. The disc starts perpendicular, turns upside down and cuts left, HARD. It then continues turning on it's axis, and starts right, where is flies gently, and then bombs abruptly. Over the flight course, it probably only goes about 100 ft forward, but strafes left and right for maybe 30-40 feet in each direction. The amount of movement it does really seems to defy logic and physics all together.