Hi,
I am Nallakumar. I have more than 11 years of experience in C# and Outlook Plugins.
Using C# and VSTO, we can develop an outlook plugin, that can handle this algorithm. There are appropriate events available to hanlde this functionality. I understand, if a user drops a task at a time, where there is an existing appointmnet, then the old appointment will get moved to the immediate slot after the current appointment (that got created with the Task).
This plugin will work on all Windows version of Outlook from Windows XP and Outlook 2007 till latest versions.
I feel the core of this can be acheived in 40 hours. I am ready for a discussion and take it from there.
Thanks,
Nalla