That was suprisingly easy:
As always, the script (Windows binary) is released under the binding terms of the GPL - let's sit back and watch the decline of eBay prices and the sudden appearance of my code in the tools of the GSM idiots.
Update: I got a couple of emails from folks for which the generated passwords didn't seem to work. It turned out that they confused the number "l" for the letter "1" and vice versa. If you find that it doesn't work for you, copy and paste the generated password from the script into an editor which has a legible typeface.