To anyone interested in how to set up an admin user permanently (without having to modify its password on initial login), it becomes easy in 1.7.x. Running the add-user.sh script like `bin/add-user.sh -u admin -p admin` has the desired effect. Unfortunately, trying to do the same on a clean install of 1.6.x is failing for me when trying to create either a Management User or Application User; I am unable to log in to the newly-created user even though the script completes without errors (and I restarted the server, of course!).
Looks like now's as good a time as any to upgrade ;)
P.S. I was bitten last upgrade when I tried to jump from 1.4.0 to 1.6.1 without stepping through 1.5.x in-between. Once bitten, twice shy.