I haven't got mines yet, but I will share what little I have learned: I'm not planning to put large holes in the wall so I want one on the desk, but not to take up space on the desk ....
I'm going to portrait mine, starting with two U2711 at first and getting the third later. so each effectively has a width of 427.83mm which are much less than limits on the following brackets (which are 600mm for each monitor)
I'm planning on using this: (MDM05)
(by default they support 2 x 24" only)
inorder for me to put these my first 'TWO U2711's' into landscape (not that I'm planning to) I need *replacement* long modules, because each can only by <=600mm in width.
popping out the short arm modules and replacing them with longer modules gives me 660mm clearance, thats approx 13mm to play with, given landscape width of 646.71mm for the U2711
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so to cut the babble short
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When Im going to landscape 3 U2711, I will probably use
MDM05 + (2 long arms) and MDM04 side by side
see specs here:
http://www.allcam.biz/catalog/index.php?cPath=29
do some measuring, its modular so modules can be replace, NOTE: I say replaced and not extended, I wouldn't advise daisy chaining them
reasonably priced TBH. approx £100
and good reviews online
otherwise you may look at solutions from ergotron
(
http://www.ergotron.com/Home/tabid/36/language/en-GB/default.aspx)
but expensive ...