I first tried this using a refractive lens, rather than pinhole; this was a single-element adapted lens, so it wasn't anywhere near as sharp as a "real" camera lens; but it only needed to resolve down to the pixel level of the video screen. Rating my paper negatives at an Exposure Index of "2", and using a Gossen Luna Pro F light meter with which to meter the scene, I measured various video frames with readings of from EV3 to EV6. With the lens set to around f/4.8, the exposure times were around 4-8 seconds. The results came out good, exposure-wise, albeit with a bit excessive contrast, which should be adjustable by tweaking the contrast of the display monitor down somewhat.
BTW, that's what I love about this process, you have the option of tweaking the image prior to exposure. In the case of using color film, you can tweak the tint (i.e. the color balance) of the display to compensate for reciprocity effects, which effects the various color layers in the film differently, throwing off the color balance.
Then I tried this using an F350, 8"x10" format pinhole camera, using the same paper negatives rated at an Exposure Index of "2". I did three exposures using this method; the first used my camcorder as a video source, with a freeze-framed image as the subject. With the TV set to normal brightness and contrast it required a 40 minute exposure. The remainder of the shooting I did on a playback of a recording from election night 2008, using my old VCR (yes, I still have several); I was ultimately able to get a good exposure at 17 minutes by running the brightness all the way up on the TV. FYI this was a 27" Sony CRT display.
I'm not familiar with the reciprocity characteristics of color papers, but I'm assuming that their paper exposure index is similar to B/W papers. I also understand that during extended exposures some of the emulsion layers end up with different reciprocity characteristics than others, throwing off the color balance wildly, requiring special filtration; or living with the wild colors.
Yep, sound like a good flat-field copy lens on a large format camera would be required for your needs. Keep us informed as to the progress of your project, it sounds interesting.