Here's the output of
brctl show on my host system.
bridge name bridge id STP enabled interfaces
admin 8000.001e689b5736 no eth0
storage 8000.001e689b5737 no eth1
However, in Cloudmin it doesn't show the storage bridge and shows xenbr0 & xenbr1, which don't exist. See attached screen shot.
Let me know if you need more info.