There are nice gadgets on the market that use the USB protocol to control your camera. With these you can make HDR's (and more) in any manner you want. Go on and google for promote control.
Great tip, thanks! Makes sense as a dedicated gadget for someone who shoots a lot of HDR (which is probably a much bigger potential audience than for this dedicated gadget
aimed at storm chasers).
I just set it up in manual mode...
...I just use the dial on the rear to manually bracket...
I wouldn't recommend doing that - in M mode, rotating the quick control dial (the 'dial on the rear') adjusts the aperture. For HDR, you need to keep the aperture constant to have the same DoF in all your shots. So, in M mode, rotate the main dial (the one behind the shutter button) to adjust shutter speed.
If you actually mean Av mode (not M mode), then the quick control dial is adjusting exposure compensation (EC), which as long as your ISO is set to a fixed value (i.e. not Auto), will
adjust shutter speed only (unless you have the C.Fn for Saftey Shift enabled, in which case aperture might
change). The probelm with using just the EC change for HDR is that you're limited to a 4 EV range (metered Â±2 EV) for most bodies, or a 6 EV range (metered Â±3 EV) for the 7D/60D. That's probably fine outdoors (especially the 6 EV range), but for many situations that's not sufficient dynamic range to cover the scene (e.g. dimly-lit interior with bright exterior windows).