I've installed 3x hitches ;-) I've had one on my X5 4.8i and my current X5M as well as my e90... I have a towing thread on xoutpost.com
Anyway. I don't believe Inivisihitch makes a hitch for the X5. I'm also not a fan of the execuhitch for serious towing as its not a receiver type hitch which rules out the use of most weight distribution/anti-sway hitches. I have used the BMW hitch, wiring harness and coding. The coding is worth it as it activates tow/haul mode on the transmission, anti-sway control in the traction control system, and if you have backup sensors it disables the rear sensors when hitched to a trailer. Also it enables a special hitching mode on the backup camera that angles your view and add special targeting to make aligning the trailer ball to the tongue simple 1 person activity.
So, no! The X5 does not come with a brake controller and its not included as part of the BMW hitch and OEM wiring harness. In most states if the weight of the trailer+Cargo exceeds 3500lbs you are required by law to have trailer brakes and of course some means to control them. This really depends on the trailer and how its brakes are designed. Frankly I tow a 4400-5300lbs trailer depending on cargo and I wouldn't want to tow without brakes. The stopping distances increase hugely without trailer brakes, like nearly 2x.
So you have several options for a brake controller. You can wire in a traditional cheap-o brake controller with its associated risks of splicing into the factory wiring, but they work. You can buy a BMW plug-n-play brake controller from some European websites, hard to find and information is scarce but super easy to install. OR finally you can go with a wireless brake controller which is what I opted for. The main reason being no splicing of the factory wiring and it allows you to tow with different vehicles as the hand controller is easy to move.
This is what I bought and I've used it on 2 different X5's and (4.8i and M) and it works great, super easy to install, and your trailer chimps cant f it up.
https://www.etrailer.com/bc-2011_BMW_X5.htm