The main limitations with projecting DV encoded video are not merely pixel count – they are the loss of detail in DV sampling, and the base problem of NTSC recording – interlacing. Neither of these problems would be addressed in your imaginative but cumbersome work flow. Any HD format would be superior, even HDV.
However, if you want to try it, just shoot as you suggested, import normally, then drop your video onto an HD Timeline. Rotate and position your 2 streams of video and be prepared to render away.
Herb Sevush
Zebra Productions