A Proposal
Much of what occurs in this passage follows the traditional Jewish Passover meal of the time. Due to a quirk of history (providence), there were two traditions of Passover at the time Jesus came into Jerusalem. One would have celebrated Passover on Thursday, the other on Friday. So Jesus is able to both celebrate the Passover Seder on Thursday and be offered as the sacrificial lamb on Friday. Toward the end, however, Jesus deviates from the Passover traditions.
First is the bread he takes and gives to the disciples. Likely this was the afikomen or that which is saved (or that to be eaten later). Depending on tradition this was either reserved for Elijah or simply meant to symbolically be saved for next year. It is possible that his taking of that bread would have been indicating his declaration that Elijah has come, that is the new Kingdom, the one that wouldn’t end, was present.
Next he takes the cup of wine. The blood of the covenant, poured out for many, is clearly the establishment of a new promise and commitment. It is somewhat debated what this language would have meant, and how closely it follows Jewish betrothal custom. Irrespective of that, Jesus’ declaration that he will not drink it again until he drinks it in his newly built home (the Kingdom of God), is a reference to this betrothal custom. At a betrothal, the bride and groom would drink a cup of wine, and then the groom would not drink again until the wedding ceremony (whether symbolic or literal is up for debate, the message remains). This is at the heart of the communion.
Jesus asks us to enter into a new covenant, a marriage covenant. The Church accepts her role as bride, and every time she drinks the cup, she declares again to the world that she is spoke for, she is wanted, and she is faithful to another. As the brides awaited patiently for the bridegroom in the middle of the night, so too do we await our groom coming for us.
whytheology 
You have missed the sense of the bread and wine. These picture from the table of shewbread in the tabernacle, the bread for the royal priesthood, and the drink offerings. See Psalm 102:9. The ash refers to a burnt sacrifice.
See also the first fruits offering restricted to when the people had entered the Land. That’s why He says he will not drink the fruit of the vine until He comes back in victory to the Land.
Leviticus 23:13 And the meat offering thereof shall be two tenth deals of fine flour mingled with oil, an offering made by fire unto YHWH for a sweet savour: and the drink offering thereof shall be of wine, the fourth part of an hin.
14 And ye shall eat neither bread, nor parched corn, nor green ears, until the selfsame day that ye have brought an offering unto YHWH: it shall be a statute for ever throughout your generations in all your dwellings.
Yes there is so much here in this passage that entire books, dissertations and the like have been written. My comments here are by no means exhaustive, and it was already a lengthy post. That said, feel free to add any other comments. Thank you