Well, i think you could create a function in your module that uses ORM methods to create the records for the new tasks, and then create an action that calls said function every week. The problem i would see is that you could end up with repeated tasks.

If you would like an outline of the code i think it would look like more or less like this....

def custom_function(self, cr, uid, context=None):
        task_obj = self.pool.get('project.task') #This get the object that hold all tasks.
        for i in range(101): #This would run the 100 new tasks.
               task_obj.create(cr, uid, {fields:value, fields:value}, context=None) #This create 100 new task.

Then you can create a cron job that calls that function.

<record id="ir_cron_100_tasks" model="ir.cron">
        <field name="name">100 Tasks</field>
        <field name="active" eval="True"/>
        <field name="interval_number">1</field>
        <field name="interval_type">weeks</field>
        <field name="numbercall">-1</field>
        <field name="doall" eval="False"/>
        <field name="model">Your_Model_Here</field>
        <field name="function">custom_function</field>
        <field name="args">()</field>
    </record>

Hope it can help you.