Currently we assume JPXDecode images are always 8 bits per component. With r9801 I added support for 4 bpp grayscale. We need to handle the full range of possible bit depths in PDF, and scale things appropriately if the stream doesn't agree with the /BitsPerComponent key in the image dictionary.
Please attach sample files in some of the desired formats so that someone can work on these. I've marked it bountiable.
I think Michael and/or Alex already fixed this. One of the PDF 1.7 FTS files has 16-bit JPX images.
Michael Vrhel fixed this for jasper. We need to confirm that these work with OpenJpeg as well.
OpenJpeg currently supports all the files in our test suite.