Farmers who have simply run out of room on their 26x26 Grand Plantations can now upgrade to the 28x28n Farm Estate. Unfortunately, as of this writing, the ability to purchase this expansion with coins is unavailable, but if you don't want to wait (or save up the coins for what's sure to be a massive price tag - after all, the Grand Plantation cost 2 million coins), you can purchase the Farm Estate expansion right now for 120 Farm Cash, a full 40 Farm Cash more than the last expansion.
To be clear, the coin option for the Farm Estate is simply unavailable right now. This isn't a case of needing to be a certain level, or needing to add a certain amount of neighbors - Zynga has simply not activated the coin option yet (when you hover over it, you see a "Coming Soon" bubble). We'll be sure to let you know when they do.
While everyone is free to wait until the coin-option is available to expand their farms, will you go ahead and pay the Farm Cash to expand your farm without waiting? If you are going to wait, how many coins do you think this expansion will cost? Better yet, how much are you willing to pay? Share your thoughts on this new expansion in the comments.