Yes tax calculator would be nice to have. It actually wouldn't be hard to build. All of the transactions are in the public ledge and can easily be retrieved via HiveSQL or Beem. Problem is tax laws on crypto are not clear and differ from jurisdiction to jurisdiction. If there were a clear formula it would be easy to implement with some simple code.
Interesting project to reward homework. Earn to learn can be a good model for Hive. I would like to learn more about it. I do like educational projects and see a great potential for them on Hive.
I don't use Twitter much, except to say something about Bitcoin or Hive from time to time. Your ideas do sound interesting. I will take a look.