Control Keyboard

I’m want to make a “control panel”, an object covered with buttons that will run various scripts when an avatar pushes the buttons.

Does every button have to be a prim containing a touch-event script?

Can I have some kind of keyboard pop up so the avatar can click on a picture?

Are there any script samples out there of things like this?

Does every button have to be a prim containing a touch-event script?

Nope. Check: http://lslwiki.com/lslwiki/wakka.php?wakka=llPassTouches

In your parent prim you can have something like:

default {
   touch_start( integer n ) {
	  integer i;
	  for ( i=0; i<n; i++ ) {
		  integer child = llDetectedLinkNumber( i );
		  string childname = llGetLinkName( child );
		  llOwnerSay( "Child Prim name: " + childname + 
							", link #" + (string) i + " touched." );
	 }
  }
}

The child/button prims don't need scripts at all.

As for rezzing a keyboard, that's a bit more wide open, certainly possible, read up on llRezObject().