cross drilled rotors

is there any reason why stock disc brake rotors could not be cross drilled as 
the high dollar ones in m***? i've used them before on winston cup and busch 
cars, but not on an lbc. seems like a lot of money just for a bunch of holes. 
i have a c&c mill that could drill the stock ones for a lot less money. am i 
missing something here?
bill r
74 midget