It is my understanding that the Hilton Hawaiian Village are currently in the process of renovating the Rainbow Mural Mosaic.
The Rainbow Tower Mural will undergo a full renovation starting at October 1st 2013 with an expected completion date of April 18th 2014.
You can see in this photo from 2011 that some tiles were missing. The environment on Waikiki is quite tough on buildings – sea salted air, salt spray from the water, humidity, all the things that buildings are not great fans of combined together.
I will make sure to take another photo similar to this so we can compare the progress!