I see it as a transfiguration story not just because the wine is transfigured, but because of the unique way in which Jesus' glory is revealed at Cana. As so often happens in John, an element from the synoptics appears much earlier in John's timeline, and it both parallels the Synoptic tradition and expands upon it. The glory that is revealed to the disciples at Cana is not the glory of a wonder-worker, but the glory of the Host of the heavenly messianic banquet. Only the disciples see it, and they are led to "believe" in him -- which is a powerful concept in John, and goes far beyond assenting to a proposal, as many scholars have noted before me.
These elements are present in the synoptic transfiguration stories that take place on a mountain top. But John's story is different, in that Jesus' physical appearance doesn't actually change. In fact, other people right around him see nothing noteworthy about him. Only the disciples see. What do they see?
To me, the key to the revelation of Cana is in the two verses immediately preceding: "'You will see greater things than these.' And he said to [Nathaniel], 'Very truly I tell you, you will see heaven opened and the angels of God ascending and descending upon the Son of Man.'" (Jn 1:51-52) I read the Wedding at Cana as a fulfillment of that promise: what the disciples (but not the other wedding guests) saw was "the angels of God ascending and descending upon the Son of Man." Of course, that image is straight from Genesis (Jacob's ladder), and it identifies Jesus, the Son of Man, as the unique connection between heaven and earth. That's the "sign," the revelation of this story.
So how does this story establish Jesus as "Beth El?" By letting the water point to him. It points to him by irresistibly taking on its heavenly nature in his presence. Why? Because Jesus is The Bridegroom: he is the host of the heavenly Messianic feast that is going on all the time,. And in the context of an earthly wedding, it's almost as if the category "wedding" is enough to collapse the great divide: as if the curtain is torn open and we -- with the disciples -- can see and experience him presiding at that feast right in our presence.
For me, one of the key elements is a cultural one: in that culture, the bridegroom of any wedding was the host. He hired the caterer (steward), provided the food and drink that the caterer served, paid for everything. And it was expensive -- days of feasting, not just one huge meal as in our current culture. That the caterer of the earthly wedding in this story gave the earthly bridegroom the credit for the wine tells us this loud and clear. That Jesus is the one who provided the wine marks him as the true host of the feast. That only the disciples knew that Jesus provided the wine, and saw that he is the true Bridegroom, is clearly parallel to the synoptic transfiguration stories, in which only the disciples (and only certain ones) are privileged to witness the revealed glory.
John is famous for moving the ascension or "lifting up" forward in his time line to the crucifixion. I'm proposing that he has also moved the transfiguration, which comes in the synoptics just before he begins his journey to Jerusalem, forward all the way to the very first experiences the disciples have of him. And the result is the same: the disciples believed in him.
I am very moved by this story, now, in a way I never was before I started looking closely at it. (I started working on this more than ten years ago.) I can almost feel the excitement and awe of the disciples as they feet the earth shift under their feet and the curtain between heaven and earth cut open as they glimpse themselves as guests at the messianic feast, and their rabbi as the eternal heavenly Host of that feast. In my preaching, I now try to invite a congregation to experience themselves as honored guests at the messianic wedding feast right in the here and now. And I've written a poem to try to capture some of the feelings of that experience. You'll find it on this site on the page "Snippets/Schnitzli/pericopies."
The work in this posting is all my own. I have made efforts to find anybody's else's work that points in the same direction, and have not succeeded. If you know of any such work, please let me know. And do let me know what you think, and if this changes in any way your preaching on this story. I'd love to hear from you. Feel free to use this reading of John's story in your preaching, but please give attribution, especially if you publish it anywhere (on line, your newsletter, etc.).