Hi Patrick,
You can use the combination of foreach, awk and cut commands to get the 
desired results. 
 
Eg:
crash> foreach RU task|grep " stack =" |awk '{print $3}'|cut -f1 -d"," |awk '{print "rd "$1 " " 3 }' > rd_stack_number
crash> rd 0xffffffff81a00000 3
ffffffff81a00000:  ffffffff81a8d020 ffffffff81a9a8a0    ...............
ffffffff81a00010:  0000000400000000                    ........
crash> rd 0xffff88106961e000 3
ffff88106961e000:  ffff884069dd8040 ffffffff81a9a8a0   @..i@...........
ffff88106961e010:  0000000400000000                    ........
The above example is some what similar to the Louis example.
-- BKS