After many, many months of procrastination and two weeks of cursing at the ImageMagick API, ABI and horrible design decisions I finished what should be a mostly working source plugin based on it. It can read a list of different images or numbered image sequences, it also allows images with varying dimensions to be loaded in one call. 8-16 bit formats with or without alpha are supported which makes it superior to anything available for Avisynth. Let the image file processing begin!
As usual the download link and special notes for the early test versions can be found in the relevant doom9 thread.