One of the guys here whipped up a couple of example signup scripts for interested resellers to have a look at, play with or install directly.  Important Note: These are not supported or sanctioned in any way by me, the author or Tucows/Blogware.  Basically we needed a way to test various signup procedures so these were created quickly, without thought of later upgrades or everyone's favorite coding style, etc. So if all of this is groovy and you want to have a go at it, here you are:

Sample Signup in Ruby
Sample Signup in Perl

Once you've installed your favorite flavor you'll notice that you can use the default Blogware domain or any other of your choosing.  The user will choose a username or enter an existing one.  The final step includes a simple captcha-ish image which the user will have to complete in order to finalize their request.  You'll be emailed a notice once the blog has been created.

Have fun!