NOTE: Newer versions of Handbrake (the "nightly builds") have much better handling of DNxHD files than 0.9.5, including 10-bit input support and bugfixes that were preventing some files from opening. Release version of Handbrake 0.9.6, containing these improvements and many more, is due shortly. Also, DNxHD 2.3.7 is available, but it does not have any major improvements for the particular workflow described in the tutorial.
Please feel free to post links to videos produced with this method, and any suggested refinements for future incorporation!
This has been a volunteer project using several unpaid contributors and spanning over a year of research. Thanks to everyone!