Found a really big heat sink with fan, that one is for CPU... the heat sink looked very effective both for its material, design and size. However, it's just very heavy.
To keep a camera on with just a small set screw in a 1.25" focuser with a small nosepiece, if that big heat sink is added, I'm sure it will drop suddenly without warning.
So, it's not really feasible.
However, I think if the whole thing is used with c mount lens, i.e. the camera is fixed by itself to the mount directly, I guess it's okay... If I were to keep myself under 150mm which is my longest c mount lens, it will work.
The bigger heat sink idea comes with the fact that my existing smaller heat sink/fan is not enough to keep the Peltier module cool at 12V, keeping a seperate 6V power supply is troublesome, and the cooling effect is not very good at only 10 degree below ambient. Let's see.