Mark and Paul's view that 2nd coming would be in their lifetime How do you explain how Mark (and Paul) thought that Jesus was going to come again (2nd coming) in their lifetimes, when this has not occurred even to this day?


  And he said to them, “Truly I tell you, some who are standing here will not taste death before they see that the kingdom of God has come with power.”


http://www.biblegateway.com/passage/?search=Mark+9

There are also references to how Paul says that there is no point getting married or that even the goods that you purchase are of no use (you won't have time to enjoy them) as the 2nd coming will happen in a twinkle of an eye.
This refers to Matthew 17, the transfiguration.  So the Word from Christ is indeed fulfilled.

Edit: My apologies for being too brief.

Matthew 17 and the scripture you quoted, Mark 9, both reveal the answer to Christ's words.  The sight of God's kingdom was the Transfiguration, the disciples present saw Elijah and Moses, who are in heaven, momentarily, and then heard the voice of God speak, which caused them to fall on their faces.

To address the second point, I'd look at 1 Corinthians 7:6-7 where Paul instructs people to marry if they so please, or to stay unmarried.


  6 But I say this as a concession, not as a commandment. 7 For I wish
  that all men were even as I myself. But each one has his own gift from
  God, one in this manner and another in that.
  
  8 But I say to the unmarried and to the widows: It is good for them if
  they remain even as I am; 9 but if they cannot exercise self-control,
  let them marry. For it is better to marry than to burn with passion.


The twinkling of an eye passage I think you are referring to is 1 Corinthians 15:51-52.


  51 Behold, I tell you a mystery: We shall not all sleep, but we shall
  all be changed— 52 in a moment, in the twinkling of an eye, at the
  last trumpet. For the trumpet will sound, and the dead will be raised
  incorruptible, and we shall be changed.


This is referring to Rapture, where we do not die but instead are changed; this is often referred to the spiritual body in non-denom Christianity, and it occurs in the last days.

Hopefully this is more helpful than my original answer!