Hi Steve. If you need to make radius bends on the smaller side (2" and less) you can use a conventional brake with a tube clamped in its fingers to bend your sheet around its radius to create the shape. Ron Fournier's 'Sheet Metal Handbook', page 29 details this process clearly. I've used this method on occasion to great effect.
If you prefer to roll larger radii, (repeatedly and accurately) like the one shown in the trick tools video, then you will definitely need to make a machine dedicated to this purpose. I don't think is a particularly difficult build either. For the adjusters on the two rolls, you could consider using off the shelf self-aligning flange units like the one I've referenced as these provide both the bearing and the sliding adjustment in one ready made, inexpensive part - although the inner bending roll won't need to rotate during the bend.
Anyways, I'm sure you'll get plenty of creative solutions to consider from other users here, but this hopefully gets the thinking process started on your way to creating beuatiful parts...
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