One silly/naive question: when producing encodes for standalone viewing (as opposed to burning to disc), why bother to encode the full 1920x1080 (or 1280x720)? Why not just encode the “active” image area (1920x820 or 1280x546)? I find that any viewer that I care to use (VLC on PC, BSplayer on tablet/phone, built-in player on my Bluray player) can handle the file and readd the black bars on its own.
Full-frame HD images retain the flexibility for those of us who do like to burn to disc. If you crop, that isn’t possible, and this isn’t true of the reverse (media player folks can handle pretty much anything, bars or no).
Wanting to maximise the encode is perfectly understandable, of course (and I’m certainly envious of anyone who can project a true 2.35:1 image in a fixed height setup without transcoding). Once these encoding specifics have been worked over, perhaps there’s mileage in releasing both cropped MKVs and BD (or at least, BD compliant) images.
By the way, I’d be interested to see the balance of folks using media centres vs. those still playing from disc. Maybe we could do a poll or something - might help indicate demand to the nice people making these projects.