What worked for me:
I got a notification saying a new update was available.
I plugged my phone into my computer and updated through Zune.
Wi-Fi was turned on (though not sure this made a difference).
After the update (not 7.8), I was informed there was another update available, which was odd--I don't know why Zune didn't install all the updates at once.
I repeated the steps above.
I kept running into an error message when it was trying to intstall the 7.8 update.
I restarted my phone and my computer, which fixed the problem, and I had a new phone...well...a new homescreen anyway!
I was disappointed in the news of our phones not getting the WP8 update, but at least they gave us the 7.8 update with the option for different tile sizes, which for me, was the major appeal for WP8. I loved 7.5, but 7.8 is just so awesome....LONG LIVE WINDOWS PHONE!!! Off-Topic: I read up on how WP is doing today, because I would be so bummed in the future if I had to switch over to Android or iPhone...nice platforms, but WP is such a breeze to work with...it's perfect for my needs. Though it's slow to grow in the market, it looks like WP is here for the long-haul...good news!