If updating your java is the actual reason behind the issue, all you would need to do is buy a more recent version of OS X.
Unless your Mac can't run one of them or something.
Reminds me of the guy who won a bet by making a successful business out of putting trash from the streets of New York in plastic bags and selling them to people.
My only concern is... don't the Tekkit and Technic installs have their own save folders?
I don't think this would be a problem unless you're moving technic saves over to your tekkit folder/server...