I am currently developing a RAW image editor that has recently gained support for OCIO configs and ACES-based workflows.
The RAW editor is called PhotoFlow and can be grabbed here:
The workflow I'd suggest in this case is the following:
* load the CR2 files in HDRMerge (
http://jcelaya.github.io/hdrmerge/), and save the output as a floating-point DNG. HDRMerge takes care of merging the bracketed shots into a single RAW file that covers the full dynamic range of the bracketed sequence. The well-exposed portions of each shot are used in the merging. Note that this is not a tone mapping or exposure fusion tool, so the output is still a linear RAW file with pixel values proportional to the scene illumination
* open the floating-point DNG in PhotoFlow, and export the result as a demosaiced 32-bits floating-point TIFF in ACEScg colorspace
This is a quite over-simplified description, but I'd be happy to provide you many more details if you are interested.
Hope this will help you!