Hi!

I have two kinects right now and I am wondering if I can add ps moves and PS eyes with the kinect to increase the accuracy. What are the limits and can I mix and match free between kinect, ps eye and ps move?

You cannot mix Kinects with PS Eye cameras.
You can use up to 3 PS Moves to track wrist and head rotations of an actor.

In near future, Is it posible to use more than 2 kinects? I belive that Kinect is more powerful than ps eye.

We are working on increasing the number of Kinects to be used. Cannot provide you any details on this, though.
Depth sensor provide data that makes tracking easier, but in exchange they have more limited range compared to color cameras. So each of devices has its own powers.

In near future, Is it possible to use more than 3 Kinect? I believe that Kinect is more powerful than ps eye

Kinect's power is that it sees depth, not just color. Thus, less cameras needed to obtain the same tracking accuracy.
However, this comes in exchange for some limitations - pretty limited range (up to 5m) and reduced frame rate (30fps instead of 60 with PS Eye).
So, PS Eye cameras still have some advantages which you may consider.

Using more than 3 Kinects does not make sense in circular camera setups, as will not provide additional accuracy. Instead, one may extend the capture area, placing the sensors in such a way that they are looking at different parts of the whole capture volume. However, substantial changes should be made to our calibration and tracking algorithms to support such distributed camera setups. We consider this as a future research activity.