I prefer IAS vs. distance
As Jabbara and Flight Safety discussed, I like the IAS at one of the TDZ markers that are on most runways. In the US, they are the 1,000 ft "fixed distance" markers. For ICAO, it's the "Aiming Point" markers, 400m (1,312 ft).
I wonder how difficult it would be to determine minimum acceleration check speeds for these points based on the selected takeoff performance (thrust and flap settings), and assumed weather and runway conditions?
In theory, all that would need to be achieved is the minimum acceleration. If you reach that speed prior to the check distance markers, you need not pay any further attention to that aspect of the takeoff.
I like that I would be looking at two things I already look at on the takeoff roll; IAS and outside. I also like knowing the progress early in the takeoff roll. This would likely avoid an abort above 100 knots