1D automaton with rule setting using HPS serial terminal
ARM video game with mouse control
ARM+FPGA+Qsys Mandelbrot video bus_master with matlab controls through ethernet
nonlinear drum with audio bus-master
Approach: perhaps the emphasis should not be on flat-out performance, but on comparision of performance and analysis of bottlenecks in hardware and in software for a given, large, task. so, rather than saying "make me the biggest drum you can", say, "make a drum of size x on ARM and in hardware and compare speed, resource, bottlenecks, power.