Harmy said:

And the mkv is definitely not going to be 1080p, because since all my current sources are 720p, I don't see any good reason to upscale everything to 1080p.

Somewhat disappointing, but any higher bitrate is greatly appreciated. My plans will still work at 720p as long as it truly is 720p with intact black bars as your other encodes have been and not 542p.

And with high bitrate 720p, compression artifacts will be even less apparent than at 1080p. So, thank you, regardless... for all your efforts.