I have been working as a sharepoint developer for some time now, and I will be able to deliver this project using sharepoint designer, and sharerpoint 2010 workflow. You will be able to select the type of activity (from the ribbon, even), and then select the user(s) and the multiple tasks for that activity. Then the user can get a single email notfication from the activity, or one email for each task assigned. Unfortunately this is a time-consuming process, hence the higher price. I am available on chat most of the time, let's talk!