If I remember correctly NESL programs are compiled into vcode a special bytecode that handled vector instructions particularly well. If vcode is ported/specialized to the commodity multicore machines and SSE instruction set, one could profitably run NESL program on contemporary machines. I do not know if there is any such ongoing initiative.

It might be the case that C source for vcode is still available so with a good optimizing compiler one could do the same. It wont quite be the same as a hand optimized assembly implementation of vcode. But perhaps still a satisfactory implementation.