Many thanks to Member D for this;
As well as Kling Klang Maschine No1, you can now get; MINI-COMPOSER, another Kraftwerk related app for the iPhone and iPad. This one was developed by former Kraftwerk member Karl Bartos and software developer Masayuki Akamatsu.
The app, described as a "simple music app for fun [that] implements the basic waves of a synthesizer with a 16 step sequencer", is available for free - with an urge to donate money to the earthquake and tsunami victims in Japan - from the Apple app store.