[BC] Question on Call Letters

[N0JAA@aol.com]

Here's an interesting question:
 
In Amateur Radio, we have callsigns in the USA that start with A, K, N and  
W, and some government utility HF stations' callsigns begin  with K, N and W.  
Is this the same with broadcast stations?  If  we were ever to run out of K 
and W callsigns (probably unlikely, but just for  the sake of the argument), 
would the FCC issue broadcast callsigns starting with  A or N?
 
Just an interesting question.
 
Paul Gray, N0JAA
Satellite Beach, FL