Thanks for the update Archlich,
I took a sample ProRes 422HQ file and sent it through TEncoder with the output as ProRes HQ.mov. I took that file into SMS13P and rendered out as DNxHD220X (10 bit).mov. I placed the original file, the encode TEncoder file and the rendered DNxHD220X file back into SMS13P, and really can't tell the difference.
Using the TEncoder to produce ProResHQ doesn't appear to adversely effect the quality. Using the DNxHD220X codec to render your "half-edited episode fragments" doesn't appear to adversely effect the quality.
You already have the TEncoder. You may not have the Avid DNxHD codec or template in SMS13P. If not here is an article explaining how to set it up.
John Refrano Avid DNxHD Template
. This works in Vegas or Movie Studio Platinum.
I have read on other forums that ProRes.mov and DNxHD.mov may not behave well in SMS13P or Vegas, when placing a lot of events on the timeline. As yet I haven't experienced this issue. Maybe I just haven't added enough events on the timeline. But, this may provide you with the solution you seek, or help find it.