I have a number of questions that stem from the text on p25 and the incomplete text involving drones and drone controllers.
-If a Battlesuit has access to Battlesuit Wargear, may it take drones without taking a drone controller as a Support System or as Wargear? (Can I take drones without taking drone controller?)
No, that's what the controller does, you have the option of what type of Drones you take, that's why it's separate.
-If a Battlesuit wishes to take drone controller as a Support, must it also have the ability (commander, team leader, etc.) to take Wargear, since the various drones are only available as Wargear? (Can I take drone controller and drones without being allowed to take war gear?)
No, it takes up a "slot" as a battlesuit system instead of being hard-wired (as wargear is).
-The text says that no model may pick the same item twice, does this refer only to Wargear, or to Support and Weapons also. Even if this applies only to Wargear, I cannot find text in the codex or the FAQ that states an exception, can a given Battlesuit take two of the same Drone? (Can I have two shield drones on one drone controller?)
It's under "Drone Controller" rules. You may take any combination of Drones.
--Many discussions and lists imply or outright state that a given squad of Broadsides can indeed have two Shield Drones, but I don't think the text supports this. I am, however, very new to Tau and I realize that I could have missed some text that would have easily cleared all of this up for me. I eagerly await clarification from you in lieu of my own natural enlightenment.