The first issue that the SAB brings up for chapter 11 is the unusual question that John the Baptist sends Jesus through his disciples, "Art thou he that should come, or do we look for another?" As the SAB points out, after what John saw at Jesus' baptism, it seems strange that he can he be so unsure. I've heard it suggested that this question is really intended to be read in almost a sarcastic tone. A lot of people expected the messiah to be a major political player, and while I don't know how much John was expecting this, he must be wondering how it could be that he's locked up in prison while Jesus is about. Apparently it was not part of Jesus' plan to get John out of prison, as John ends up dying there.
The SAB asks in response to verse 11, "Who was the greatest: Jesus, Solomon, or John the Baptist?" I don't think this is a contradiction, but if you want to make this sort of comparison, why not throw in Moses, as I'm sure you could dig up one or two verses in this strain. The reason I don't think this is a contradiction is that each of these men is considered the greatest not overall, but within certain constraints. Solomon was greatest in wisdom, John the Baptist was greatest in religious piety, and Jesus, being God in the flesh, is in a category of his own and can't be reasonably compared to anyone. (Yes, I know that Matthew 12:42 and Luke 11:31 are making that comparison, but you could think of it like comparing the world's smartest dog to the world's smartest person.) Verse 12 is another one that I'm with the SAB on, in that I have no idea what it's supposed to mean.
Was John the Baptist Elijah? This is a tricky one, and the SAB actually supplies the answer in unusual style: Jesus said he was, so he was. I'm guessing that this is mentioned in a mocking matter, since the source of the contradiction is John's own denial in John 1:21. It does seem silly that John wouldn't know, doesn't it? I think that the real substance of the issue is symbolism vs. literalism once again. Jews are waiting for the prophet Elijah to return. Rather than dying, in 2Kings 2, Elijah went up to heaven in a whirlwind, and the prophet Malachi said (in Mal. 4:5) that he would come back before the "day of the LORD", which most took to be the time of the coming of the messiah. So in Jesus' day, many people were wondering how Jesus could be the messiah if Elijah had not appeared, and my take is that Jesus is saying that John the Baptist fulfilled the symbolic/prophetic role of Elijah. (For what it's worth, many Christians still believe that Elijah will literally return before Jesus comes back at the end of the world.)
In verses 21-24, Jesus seems to be condemning a number of cities for not responding to his preaching. I think this is another case, not of actually condemning, but of observing condemnation. That is, I don't think Jesus is saying he's going to punish these cities; he's saying that their lack of faith will end up being its own punishment in the end.
I'm pretty sure that I addressed the question of who is the lord of the earth back in chapter 4.