Note that at least for resampling we might have already what you need. It is a CLI we use in our AVID pipline. It is for mapping, but no registration given, it is just a versitale resampler for images.
OK, I see. If you just need a simple GUI, it might be a solution to build that arround the same codebase the matchpoint mapping plugin uses. See QmitkMatchPointMapper::SpawnMappingJob(). There everything for sampling images is packed together. If it is realy just a simple resampling, then it might be faster and cleaner to directly use itk resample image filter.