Okay so as crazy as this might sound to all of you, I have been hearing several rumors that Innistrad set to release later this year will actually be a Ravnica revisit.
Couple bits of info to back up this rumor:
1. Back in between Rise of the Eldrazi and Scars of Mirrodin, Wizards announced on their daily blog that they were going to avoid creating new planes for a while.
2. Liliana, as the poster girl for Innistrad looks as though she's sitting on a throne (obviously). Possibly a Orzhov guild room.
3. Although the guilds fell in Dissension, there are some who still work out the guilds in secret. Storylines from the books Agents of Aritifice and Test of Metal can confirm this.
4. Agents of Artifice and Test of Metal also layed quite a bit of storyline build up for Liliana. For one, we know that she made deals with at least 4 different demons to maintain eternal life, and its time to pay up to them. In the Agents, she helps Jace overthrow Tezzeret to gain control of a multiplanar merchant company to return it to Nicol Bolas in exchange for his help in destroying these demons. While they did overthrow Tezzy she did not gain control and therefore could not return it to Bolas, so that plan right there went out the window.
5. One of the Planeswalker comics depicts Liliana and Garruk fighting (which was the inspiration for the duel deck box). Shortly after their fight, Liliana is sent by one of her demons to go find the chain veil, a veil that holds the power of 1000 souls. Liliana finds it, and puts it on, gaining its power but walked off with it. Whether she delivered it to the demon, or if she still has it is unkown.
6. Considering she as at least 4 demons tailing her, they are sure to send some kind of phantasmic and horrible creatures at Liliana, thus the tagline "Horror Lurk Within"
7. Liliana spent a good time on Ravnica after the Guilds fell in Agents or Artifice (Nearly a year or so). It is possible she heard about the remenants of the Orzhov. If you have trouble fighting off demons you owe a debt to, what better place to try than the guild of deals?
8. Finally, probably the best piece of info comes to light. A book was written for the magic storyline that was supposed to be a sequal to agents of artifice along with test of metal. It was called curse of the chain veil (referring to the veil in the comic). The book was entirely finished and published, but yet was not allowed to release. Why? because of Innistrad. The Agents/Metal/Veil books all heavily revolved around Jace, Liliana, and Tezzeret. As of the end of Test of Metal, Jace was on the run from Tezz. Considering everything he owns is in Ravnica, and the population of the plane, it is very possible he is hiding out there.
9. WARNING THIS POINT HAS SPOILERS ABOUT THE BOOK "QUEST FOR KARN"
I have just finished reading Quest for Karn, and the last I read of Tezzeret, he was leading half the phyrexians against Glissa and her force of Phyrexians. There was no indication of who won the battle, but considering that Tezz is a walker we can safely guess he prevailed. I don't imagine he'll be coming back to Ravnica now that he has control of Phyrexians but at the end of Test of Metal he said that if he ever guessed that Jace did not fear him enough, he would come find him so theres a possible loop to that.
10. It is likely that Garruk is coming back in Innistrad despite having a reprint in M12. In the web comic, he was cursed by Liliana during their fight and it is possible that he is looking to either get revenge or get cured. Wizards also released they will release a card called "Garruk the Enlightened" Which is possible that the card could be G/B even though black really isnt an elightening color. But a G/B walker would be interesting for Golgari play if this rumor is true.
Keep in mind this is all just speculation and rumors. I could have this all wrong and just be babbling like an idiot here but this is just info i gathered xD
so thanks for reading, if you have any thoughts on the subject or any additional info please post! thanks!
--Church