My recommendation would be, if you wanted to go mono RGB filter imaging, you'd go the
http://www.zwoptical.com/eng/Cameras/ASI120/index.asp
I've not seen enough results using the colour version, therefore the Imaging Source DBK618 or the DFK618 might be the go.
The biggest problem is working out which system to go with & your local overall conditions will decide this for you..3X the work with the mono/RGB filter route & added expense.