You can do it if you are really into it and careful enough. Get some adhesive tape before daring it. The first teardown work is here: http://www.iclarified.com/26218/first-teardown-of-the-new-27inch-imac-photos.
Be careful, the teardown is not as elaborative as we see here with iFixit. You need to get some ideas from New iMac 21.5-inch iFixit tear down. It's here: [guide|11936]
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