Takeoff performance monitoring has been discussed here several times over the past two or three years, and probably in connection with every over-weight takeoff incident for even longer.
Various high-tech and low-tech solutions are put forward, arguments against them rolled out, and everything goes quite again.
The simplest approach I have seen is to compute the expected time to V1, or ideally some lower speed, something that should drop out easily from the routine takeoff calculations, and then abort the takeoff if the reference speed is not reached in the calculated time.