Automating blog creation : Blog Templates, Batch Create and cron?

We're developing a workflow to ease what has been a manual process to create (portfolio) blogs for students. I'm looking at Blog Templates and Batch Create. It has been discussed before that Batch Create might support specifying a template when a blog is created. We would like this feature.

As it stands, we will need to set the default template for the new blogs before we run Batch Create and remember to change the default template to the default-default afterwards. But we have problem, we create blogs automatically for new users. New users will get the wrong defaults if they log in while we are batch creating new blogs with a specific template.

To mitigate this we could batch create blogs at time when we believe new users won't try to register and put the site in to maintenance mode. It would be unfair to ask an academic to run a batch create outside of working hours. So my question is... Is there a cron type tool where we can set up maintenance mode, set the default template, batch create the blogs (using a prepared XLS file), run the queue in Batch Create, reset the template default and unset maintenance mode?