such is the fun when an analog system (film) goes digital and confusion about measurement and calibration multiplies.....In case someone doesn't get it:
You won't see more steps in a shot of a transmission step wedge by downscaling, the downscaled image will look exactly the same unless you downscale so much that you see pixelization. If you compare a shot taken with a 8mpix sensor against shot taken with a 36mpix sensor where each pixel has exactly the same DR in both sensors however...
You will see the exact same DR in both shots. No different then if you shot 8x10 Velvia 50 and 35mm Velvia 50 and compared them in terms of DR.
First of my examples yes you will same DR, second of example wrong, you will see different DR and that is precisely why comparing print DR makes sense and screen DR is of limited value. If signal to noise performance per pixel is equal, a higher megapixel sensor will always capture more information. Why this happens is already explained in one of the other 2000 DR threads here.
As dtaylor previously stated, there's a difference between the generic definition of dynamic range (as applied to signals of all types) and the meaning of photographic dynamic range. Get a Stouffer step wedge and a light table and try it out...
I come from an electronics background and to me, it's SNR (Signal to Noise Ratio) to measure performance of electronics, not DR. I have always thought of DR as the equivalent of "stops", an observed/perceptual scale, not a measurable scale with electronics test equipment.