On the Phoronix Forums, Roderick (a.k.a. Thunderbird) said he hopes to release a new version of NVClock but lacks the needed hardware or people to test out the NVClock code on their NVIDIA hardware.
If you are interested in helping out Roderick with either development work or testing out NVClock code, place a message in this thread. He is mostly in need of testers that have access to GeForce 8 and GeForce 9 hardware.
While NVClock now uses CoolBits with the NV Extension for much of the legwork, it still has a low-level overclocking engine for some GPUs as well as fan control support for some graphics cards, faking a GeForce GPU as a Quadro ASIC, and various other features.
If you're looking to do more help in better enabling the open-source NVIDIA scene, the Nouveau driver could always use testing especially on the newer graphics cards.