I suspect setting the camera to take two or three frames per segment of the series would be quite easy to do (considering that they are using control software) and running the shots through a good HDR program before stringing them together would just take time and not be too hard - any minor motion between the combined frames would be hidden by the fast change of shots in the series that makeup the time-laps
Tools of the trade: Canon 400D, Canon 7D, Canon 70-200mm f2.8 IS L M2, Sigma 120-300mm f2.8 OS, Canon MPE 65mm f2.8 macro, Sigma 150mm f2.8 macro, Tamron 24-70mm f2.4, Sigma 70mm f2.8 macro, Sigma 8-16mm f4.5-5.6, Raynox DCR 250, loads of teleconverters and a flashy thingy too
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