DIY Isolated Power Strip?
That will, in principle, work fine. 

The biggest thing to watch out for is physical connection, especially stress relief. You've got your isolation transformer hanging off the end of your mains connection, and it's very easy to overstress the connection. Also make sure that your electrical connections are properly insulated. Electrician's tape is NOT a long-term insulator. The connections themselves must be entirely free of mechanical stress.