@IDA_ML -- here's something you can try - no coding skills needed
Not sure if you're on Mac or Windows but I believe you mentioned that you have MLVFS working on your system. That's the first app that used the focus pixel map files and what I still use when experimenting with new resolutions. Dig into the app and look for a file named, "80000346_2592x1108.fpm" now make a copy and name it "80000346_2592x1332.fpm" and try it on your MLV files.
Long answer.
If you extract the DNG's without chroma smoothing then process a DNG frame with dcraw using the -4 -E options you can clearly see the focus pixels.
and this is what it looks like in color:
Looking at the sample files with mlv_dump using the -v option we find this:
Block: RAWI
Offset: 0x00000034
Number: 1
Size: 180
Time: 0.910000 ms
Res: 2096x1180 <--- image size
raw_info:
api_version 0x00000001
height 1332 <--- full raw buffer is 2592x1332
width 2592
That's the same full raw buffer width as in zoom mode but with increased vertical resolution. Now the question is if the crop and pan metadata works the same? This is what is needed to line up the focus pixel map file--the map files cover the full raw buffer so they can be used with all of the various image size and aspect ratio options.
It works!
Well almost. Focus pixels show up at the bottom of the frame because the focus pixel map file that is currently in MLVFS doesn't completely cover the new full raw buffer.
So all that is necessary is to extend the zoom mode focus pixel map file to cover the additional vertical resolution and we should be able to eliminate the focus pixels on this new crop_mode resolution.
[EDIT] Here are before and after images showing the MLVFS hack. You can zoom into them in flickr without having to download the file to take a close look at the focus pixels.
Before:
After:
