Now that we have the book, it isn't as big of a deal, but it is still nice to have a list of good study resources (e.g. whitepapers, presentations, videos, etc.) While searching for a simple table of subcarriers and pilots (page 14 or the Survival Guide, but I couldn't find it. Google found it an eighth of the way down the page at http://chimera.labs.oreilly.com/books/1234000001739/ch02.html,) I found a really excellent pdf of presentation slides. That made me realize I haven't seen a list of good resources, other than the official "the book is delayed, try these" list. It is time to start one. (If a list exists elsewhere, please let us know.)
Here are the official suggestions:
1) 802.11ac A Survival Guide - Matthew S. Gast - O'Reilly - http://www.amazon.com/802-11ac-Survival-Guide-Matthew-Gast/dp/1449343147/
2) Aruba Network's 802.11ac In-Depth Whitepaper: http://www.arubanetworks.com/pdf/technology/whitepapers/WP_80211acInDepth.pdf
3) Ruckus Wireless 802.11ac Whitepaper: http://www.ruckuswireless.com/whitepapers
4) BYOD and Beyond Whitepaper from Aerohive: http://www.aerohive.com/pdfs/Aerohive-Whitepaper-BYOD-and-Beyond.pdf
5) Aruba Network's BYOD Whitepaper: http://www.arubanetworks.com/pdf/technology/whitepapers/WP_BYOD.pdf
6) Motorola BYOD Whitepaper: http://www.motorolasolutions.com/web/Business/Products/Wireless%20LAN%20Devices/_Documents/_static%20files/BYOD+-+Bring+Your+Own+Device.pdf
7) MTI's BYOD Whitepaper: http://mti.com/Portals/0/Documents/White%20Paper/MTI_BYOD_WP_UK.pdf
I found this set of presentation slides very good: http://www.arubanetworks.com/pdf/events/GigabitWifi_802.11ACInDepth_PeterThornycroft.pdf
I just skimmed this, but it looks excellent: http://cdn.rohde-schwarz.com/pws/dl_downloads/dl_application/application_notes/1ma192/1MA192_7e_80211ac_technology.pdf
Other suggestions? I will update as I find more things.
P.S. How does one create a hyperlink here?
Another excellent whitepaper, this time from cisco. It is written in comfortable language, and covers to a good depth.
I found "2.3.2: Differences Between 802.11ac and 802.11n" especially helpful.