The Pandora-Elevation Deal that Never Closed and a Mid-2011 IPO?

Back in August we reported that Elevation Partners had signed a letter of intent to buy secondary shares in Pandora, the long-suffering, now-hot online radio station. I wondered what ever happened to that deal, so I started digging. As it turned out, shares were sold but Elevation didn't get them. Here's what we've been able to piece together, from several sources on different sides of the negotiating table.