This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
As far as I know you can't get the current cursor and enlarge it. You probably could if you could convert it to both an Image and a "hot spot" Point; you could then enlarge the Image, scale the Point, then call Toolkit.getDefaultToolkit().createCustomCursor with those values.