I'm not aware of any early Christians who wrote of Jesus manifesting himself in theophanies. The pre-mortal existence of Christ is a far more involved and complex issue, especially when theologians reconcile this with the doctrine of Trinity. As noted in a response above, Justin Martyr seemed to think Christ alone manifested himself in the OT. Martyr writes:
Like a king would send his son, he also being a king, thus did God sent Him. He sent him as God. He sent him as to men. (Epistle to Diognetus, VII)
I'm having trouble finding a good English translation, but here is the Greek text: http://www.ccel.org/l/lake/fathers/diognetus.htm. I'd highly recommend reading the whole chapter to get context.
Thomas Aquinas, on the other hand, seems to think that this manifestation is much likelier coming from the Holy Spirit, especially when in light of Summa Theologica 31:3 in combination with 'Ipse Actus Essendi subsistens'
Yet [God, the Trinity] does not mean the relations themselves of the Persons, but rather the number of persons related to each other; and hence it is that the word in itself does not express regard to another. (Summa Theologica 31:3:Reply to Objection 3)
Translated as 'act of being,' the expression actus essendi refers to a fundamental metaphysical principle discovered by Saint Thomas Aquinas (1225–1274) in his Christianizing of Aristotle.
Aquinas saw that in any subsisting extramental thing one finds a couplet of metaphysical principles: one is the ‘essence’ which makes the thing to be what it is, the other is the actus essendi which gives to the thing and to its ‘essence’ actual existence. (Wikipedia Entry, Actus Essendi)
In other words, Aquinas didn't buy into the fact that God was ethereal and shapeless, but a being of physical and metaphysical construct.
Anyway, to directly answer your question, there isn't any evidence we have to suggest that God or Jesus expressed themselves in theophanies, at least according to early Christian writers.