An interesting post was spotted on the GeForce forums. Nvidia Enables laptop overclocking again after a bucket-load of critique. You need to read carefully though as it states that only certain models will allow it.

In a new driver release Nvidia will enable it again, that driver release however is next month. if you already like to use overclocking for your laptop, you can use the 344.75 driver.

Nvidia:

As you know, we are constantly tuning and optimizing the performance of your GeForce PC. We obsess over every possible optimization so that you can enjoy a perfectly stable machine that balances game, thermal, power, and acoustic performance.

Still, many of you enjoy pushing the system even further with overclocking. Our recent driver update disabled overclocking on some GTX notebooks. We heard from many of you that you would like this feature enabled again. So, we will again be enabling overclocking in our upcoming driver release next month for those affected notebooks. 

If you are eager to regain this capability right away, you can also revert back to 344.75.

Well ...