About overclocks....
There is an on-going thread over at the XDA forums about overclocking on the Galaxy Nexus. So far, 1.4Ghz has been achieved, however there are problems. Some people experience major slow downs and stuttering at 1.4Ghz. 1.6Ghz has also been achieved but it is far from stable. XDA members are finding that there may some very huge limitations with the hardware that will actually not allow for major overclocks.
It is unfortunate, however the good news is that the undervolting has been a great success so far. XDA members have found that the stock voltages are set extremely high. They've been able to bring the stock voltages down quite a bit, almost drastically. What does this mean? It means longer battery life. A significant increase in battery life should be achieved with lower voltage.
I'm sure in time they will be able to achieve a more stable overclock, however early attempts so far have been quite the challenge.