Although not Biblical in terms of a response, I believe that this verse from a Garth Brooks song speaks wonders:

"Sometimes I thank God for unanswered prayers
Remember when you’re talkin’ to the man upstairs
That just because he doesn’t answer doesn’t mean he don’t care
Some of god’s greatest gifts are unanswered prayers."

Could it be that what you have asked for (or would like to ask for) really isn't in your best interest; or that the Lord has different plans for you than what you may be asking for?

Could it be that although you haven't received your request...possibly God will answer your call when He feels it will/would/could best benefit you?

Stand by your faith in the Lord, and believe that He does have your best interest in mind...even if you may not understand why your prayer/prayers aren't answered in a timely fashion. 

faith.......believe through faith....
when i have a hard time understanding or believing a verse.....i simply say it
claim it
and pray it!
trust me it works....faith comes through hearing and hearing is in the word of god! 

When we become so intune with the Holy Spirit, and the Bible (you shall worship me in spirit and in truth) whenever we pray, we pray God's will back to him, thus praying in Jesus' name

Wala we get what we want...