I think you would be better of creating your own clone of the blog as an external project and using a different prefix for the stored procs and tables. I've done this before when one of my customers needed a custom blog. It basically copy paste, edit namespace and tables scripts, use a new guid for the feature guid and put all the files into a new folder.
The problem is by modifying the existing one you are basically forking the code and making it difficult for yourself when you want to upgrade mojoportal later on.
Best,
Joe