@amendegw: Thanks for the offer, but it's really unnecessary. Currently I'm using Vegas to hard-render to 1920x1080i into DNxHD, then importing that into Handbrake for 720p/2mbps encodes using the original very useful settings posted above by musicvid.

I would post more thoughts on the whole thing, including some stuff I was experimenting with last night that apparantly contradicts "common knowledge", but as an inexperienced fellow my findings hold no weight, so I'll just keep them to myself from now on.

FInal, happy thoughts: my videos look better than they did before I started re-researching my encoding settings, so I thank everyone who has helped me in this post. Your assistance and hand-holding has been honestly much appreciated.

Edit: typo!

Aww come on Sunflux. I love it when common knowledge gets contradicted. It helps us all challenge/change/reinforce what we think we already know.

Well, my findings only have to do with DNxHD encoding into Quicktime.

Can you tell me, are these statements accurate:

1) Quicktime, as a container format, is incapable of working with non-square pixels and requires a PAR of 1:1.
2) This means Quicktime movies encoded with non-1:1 PAR will not display correctly - they would appear squished or stretched.
3) Ignoring the -TR variant, DNxHD encodes all input at 1920x1080 or 1280x720 resolutions.
4) DNxHD does this because of the Quicktime 1:1 PAR constraint (and also because it was intended for HD use).
5) Since DNxHD will internally up-sample unsupported resolutions, you should always feed it 1080 or 720 at 1:1 PAR for best quality.

"Can you tell me, are these statements accurate:"

After a three-day marathon, this thread seemed to just fall off a cliff with a question from Sunflux. Even though he didn't use a question mark someone should comment on his final assumptions. Though I'm curious, at the moment, that someone ain't me.

The DNxHD templates do not trump the Custom Render Properties in Vegas, with very few exceptions. Specify 1920x1080 1:1 PAR, or 1280x720 1:1 PAR, or set one of these first as your Project Properties.
HTH

"The DNxHD templates do not trump the Custom Render Properties in Vegas, with very few exceptions. Specify 1920x1080 1:1 PAR, or 1280x720 1:1 PAR."

Which means, for 1440x1080-60i AVCHD, the pixels have to be resized in Vegas to match the 1920x1080 1:1 PAR input requirement of DnxHD.

Excuse me for restating the obvious, I'm on a bio-rhythm low for all three phases. I haven't gotten the Vegas settings correct after a few feeble attempts last night. I'm working on your "Better" option.

Put 1440x1080 source in a 1920x1080 1:1 PAR project.
That sets the default custom render settings.
Use the 8-bit 1080i template in Handbrake.
Should work.