Macbook Pro Retina with more than 2 external displays
You can absolutely use display link drivers. I have an Intel Iris Graphics 6100 1536 MB graphics card in my 8gb Mac Book Pro (early 2015) 13 in. It drives 2 24 in Dell displays via with mindvi (normal fps) and four other Dell 24 in monitors using usb 2.0 -->minidvi adapters at 12-15fps. Not great for video or gaming, but just fine for email/documents/command line/etc. I still get full FPS on the two other monitors, so I'm not without media...  3.0 I imagine would be better, but more taxing on the system. 

Anyway, my opinion is that this will work even though Display link is a little buggy and support is not great. I love the mini display devices. Like I said, I imagine 3.0 would offer a lot better FPS... but I appreciate the price point and that the system is not heavily burdened by the 2.0 devices. 

As you can see on the left I have (besides terrible cable management skills) a 7 port usb 3.0 hub off of which these four displays split. I have two small 4 inch fans pointed up at the display link adapters, and my computer is kept elevated on a small stand. The laptop is is new, and my room is air conditioned with a dehumidifier and a HEPA filter to keep dust from deteriorating the impact of internal fanning systems... but my machine does not run hot at all: 

My 2013 mac book air can drive 5 displays... for some reason I am hitting a limit of 4 display port devices. You may have better luck though... 

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