With 8 3-pin Molex connectors and a customizable fan curve, both or without required software. I would prefer it to be fully internal, not in a 5.25" bay or fully external (though if there are no good internal controllers, that would be okay).
I'd use your mobo - http://www.asus.com/au/Motherboards/RAMPAGE_V_EXTREME/specifications/ - with 4 fan splitters. That way you can control fanspeed with mobo uefi software "Rampage V Extreme has 8 x 4/3-pin (PWM/DC) combo fan connectors, four intelligent onboard sensors plus three additional 2-pin headers and a selection of three thermal cables to help you monitor the temperatures of up to seven motherboard or key components in real time — so you're able to adjust CPU and case coolers automatically or manually for the best dissipation."
That being said, I don't think you can control 3pin fans speed via the motherboard.
The only way to change their speed is via voltage or power. So the link I provided you will not accomplish your goals.
Maybe someone with more insight on that specific matter can offer their input... I'm not sure if you can regulate a 3pin fans speed via mobo.
Never mind, I found what I was looking for: the NZXT Grid.
The grid does not enable you to control the fan speed. With the grid, it would run at 12v (100%).
You would need the grid+ to change fan speed. Or the splitters I linked.
(I found out they would work )
I'd use your mobo - http://www.asus.com/au/Motherboards/RAMPAGE_V_EXTREME/specifications/ - with 4 fan splitters. That way you can control fanspeed with mobo uefi software "Rampage V Extreme has 8 x 4/3-pin (PWM/DC) combo fan connectors, four intelligent onboard sensors plus three additional 2-pin headers and a selection of three thermal cables to help you monitor the temperatures of up to seven motherboard or key components in real time — so you're able to adjust CPU and case coolers automatically or manually for the best dissipation."