Hello,
I'm prototyping a Mac app that stacks raw files and produces a DNG as output. It is a purely raw workflow—the latent image is never "developed" or demosaiced, and the output file is a true raw file. In that sense, I believe it's similar to Sony's Pure Reflections workflow.
My app is fully self-contained and does not require that the raw files be converted to DNG. In fact, it does not require you install any third-party software at all, such as Adobe's DNG converter.
I thought there might be interest among participants in this thread. If you'd like to try it, please PM me with your email address. I'm looking to share it with a small number of people at the outset.
Cheers,
Michael Allman