i wrote a routine in excel thatll print out random single-note melodies in tablature, or another one thatll print out random rhythm patterns...
if anyone is interested i can tell you how i did it or send you an email with those excel-files...however im not sure if theyll work since i used the german version of it...
oh yeah ...theres lots of progs on the net thatll generate random music...now i never tried this, but i guess some of those progs will let you save those randomly generated melodies as midi files...which you could then import into the power tab editor... :)