So I'm wondering if this is a bug or something but doing some testing with 3xCrop mode on 5D2 with
build from dfort Dec./1/2016 . Just the basic modules for raw video.
With raw_rec (mlv lite) in fine resolutions 10 & 14bit 2152x1072 is the max. selectable resolution, while in 12bit I can expand the size to 2152x1076 but not 10 or 14bit.
Should it not but the same thought out the bit range ? Too bad the image are dark pink not very easy to correct like bad black levels , Good thing thou is in 12bit with Full MLV+audio in
3X crop mode I have perfect corruption Free recording

with correct black levels in All Liveview modes , but only the canon preview was glitch free no Lv freeze or B/W lines mess .
Thou framing is off it doesn't freeze up very useable and with audio too . I didn't try 10 bit in 3x Crop to see if it's a problem will try later , so it seems 3x crop recording to MLV 2.0(full)
works in 12bit corruption free (useable).

Edit: Sorry the size in 3xcrop MLV 2.0(full) was 2144x1076 @23.976p