getting a camera with a high shutter speed willl not make your shots super slow mo - shutter speed refers to the amount of light let into the camera and not the number of pictures it takes a second. if you buy a camera with a high sutter speed it wont get you anywhere, its FPS that is important, something that only the likes of studios/bbc etc have any real need/access to.

If you want to get some very good results I suggest you shoot in PAL and use some type of frame inteperlation program. I have used both 'twixter pro' and 'retimer' (aswell as the 'timewarp' effect in after effects) and if the footage is shot right the results are amazing.

heres the examples:
RE:Vision Effects, Inc. : Products: Twixtor
REALVIZ ReTimer Pro