Does SRaw mode do anything to help this situation?
Theoretically it could reduce your resolution sampling, or perhaps offer some alternate compression scheme?
I don't think so, the "usable image" is already just about 1080p so sRAW might shrink that too far, like 240p (I haven't done the math though).
They need is a way to compress in real time while saving the resolution where it is at
or a way to crop the image in real time
or a way to increase buffer speeds
or a way to increase buffer capacity
actually all of the above
they're working hard looking for an answer but I wouldn't expect continuous 14bit DNG video, honestly I'd just be happy with 10 seconds (which is already asking a lot from this hardware).
Though I wonder, are the 14bit DNGs are using the same "pipe" that the Camera uses for writing CR2 files to card? What if they were converted to CR2 rather then DNG? Would that allow them to use a bigger or faster buffer? Probably not though cause I assume CHDK's DNG converter is already using Canon's built in CR2 converter.