I think whether this gets done would probably turn on whether arena issues get resolved. As Carolija mentioned, the first big stepping stone is whether the Maloofs would pay up for the big money that Adelman would demand. They've shown in good times that they'll spend money, but if the arena issues are still unresolved, that means cash flow is still a big problem. Further, if the Kings end up moving there's no way Adelman comes back- he would lack the connection to the team/fanbase, and the Maloofs would want to start creating a new identity and have no reason to bring back an old Sacramento connection.
If the arena plans go forward, however, I'd see this as a real possibility. It means that money will quickly become less of an issue, and the Kings will want to get a sort of Sacramento-renaissance to start happening, and what better way to do that than with the best coach in team history? New arena and new players is perfect for a fresh start. I also think that over the past few years the Maloofs have seriously been humbled by how bad things went and how quick. From the Houston Chronicle interview, it sounds like Adelman was reminiscing about better days as well.
I'd remind you guys that what Phil, Kobe, and the Laker's management went through was far worse. If those guys can mend their problems and get back together, I don't see why it couldn't happen here.