Mary Magdalene was the Beloved Disciple.

Now most people proposing that theory do so while claiming the Text of the Fourth Gospel must have been changed in some capacity.  I do not, the two passages commonly taken as distinguishing her from them are when analyzed closely actually saying the opposite.

John 20 verses 1-2.

The first day of the week cometh Mary Magdalene early, when it was yet dark, unto the sepulchre, and seeth the stone taken away from the sepulchre.  Then she runneth, and cometh to Simon Peter, and to the other disciple, whom Jesus loved, and saith unto them, They have taken away the Lord out of the sepulchre, and we know not where they have laid him.

The key word here is "other" no other Beloved Disciple verse says that, the implication is that the primary Disciple to whom that title belongs was someone already in the scene, which only leaves Mary.  

Add to that how this is the only Beloved Disciple verse using a form of Philia instead of Agape and it clearly isn't good for ruling anyone out.

Now look at John 19:25-27, my personal translation.

Now there stood by the cross of Jesus his mother, and his maternal sister Mary the wife of Cleophas, and Mary Magdalene.  When Jesus therefore saw his mother, and the disciple standing by, whom he loved, he saith unto his mother, "Woman, behold thy son!" Then saith he to the disciple, "Behold thy mother!" And from that hour that disciple took her unto his own home.

As an aspiring writer myself it's clear to me that when Verse 25 describes a group of people including his mother standing by The Cross, then verse 26 says Jesus observed two people standing by, the intent is clearly that both people referred to in verse 26 are among those identified in verse 25, not merely one of them.

"But sons are male!" you may object.  It is already the point of this passage that Jesus is giving the legal responsibility of being her son to a person who's not literally biologically her son.  So likewise I don't think the biological sex or gender identity of the Disciple in question matters either.

Likewise the pronouns used here and at the end of chapter 21 may not be as gendered in the Greek as the translators assumptions have lead us to believe.  But even if they are it could be because of this legal sonship and nothing else.

I also now believe Magdalene and the sister of Lazarus & Martha are the same Mary.  In John 11 when you see a from of "love" in the English, in the Greek a form of Philia is used both times it's only referring to Lazarus in verses 3 and 36, but Agape is used when it refers to Lazarus and Martha and their sister together in verse 5.  Elsewhere in the same chapter the remaining sister is named Mary, I think this chapter which proceeded all the usual Beloved Disciple passages sets the precedent that Mary will sometimes not be referred to by name but as someone Jesus loves using Agape.  This also results in my concluding the other disciple who Jesus loved Philia in chapter 20 is Lazarus.

I've talked before about my belief that there has been some slight corruption in the letter of Polycrates.  

"We observe the exact day; neither adding, nor taking away. For in Asia also great lights have fallen asleep, which shall rise again on the day of the Lord's coming, when he shall come with glory from heaven, and shall seek out all the saints. Among these are Philip, one of the twelve apostles, who fell asleep in Hierapolis; and his two aged virgin daughters, and another daughter, who lived in the Holy Spirit and now rests at Ephesus; and, moreover, John, who was both a witness and a teacher, who reclined upon the bosom of the Lord, and, being a priest, wore the sacerdotal plate. He fell asleep at Ephesus. And Polycarp in Smyrna, who was a bishop and martyr; and Thraseas, bishop and martyr from Eumeneia, who fell asleep in Smyrna. Why need I mention the bishop and martyr Sagaris who fell asleep in Laodicea, or the blessed Papirius, or Melito the Eunuch who lived altogether in the Holy Spirit, and who lies in Sardis, awaiting the episcopate from heaven, when he shall rise from the dead? All these observed the fourteenth day of the passover according to the Gospel, deviating in no respect, but following the rule of faith. And I also, Polycrates, the least of you all, do according to the tradition of my relatives, some of whom I have closely followed. For seven of my relatives were bishops; and I am the eighth. And my relatives always observed the day when the people put away the leaven. I, therefore, brethren, who have lived sixty-five years in the Lord, and have met with the brethren throughout the world, and have gone through every Holy Scripture, am not affrighted by terrifying words. For those greater than I have said 'We ought to obey God rather than man'...I could mention the bishops who were present, whom I summoned at your desire; whose names, should I write them, would constitute a great multitude. And they, beholding my littleness, gave their consent to the letter, knowing that I did not bear my gray hairs in vain, but had always governed my life by the Lord Jesus."[Eusebius, Church History, Book V, Chapter 24]

I believe the "John" of this letter was originally either not named at all or was named Mary.  I also think it's a misinterpretation of the letter to think this Disciple is wearing the Brest Plate of the High Priest, that reference is tied to them being who rested on the Bosom of Jesus in the Fourth Gospel, I think they symbolically are the Breastplate with Jesus as the High Priest.

There are known traditions independent of this that say Mary Magdalene came to Ephesus, but they usually involve her coming there with "John" and Mary the Mother of Jesus, among those is Gregory of Tours.  Since the earliest Christians of Southern France were Ionians who migrated there in the 2nd Century the later tradition of Mary going to France could derive from the Ephesian tradition.  

Still I am skeptical of her even going to Ephesus, she may be among the Early Christians buried at the Dominus Flevit Church on the Mount of Olives.