Well, if you want to use a variable you can.
Eg.
_x = 5
_y = 6
_z = 2
_camera camsetrelpos [_x,_y,_z]
Alternatively, you could use a random function.
_x = random 15
_y = random 15
_z = random 15
_camera camsetrelpos [_x,_y,_z]
You might want to play around like adding numbers or multiplying them to the random in order to make them better. The example above could generate 0.0045 or something rediculous, so you might want to play around with it.