"I'm not sure how unique it is."
Trust me on this one. My Liddel and Scott (the big one with all the representative citations from classical and patristic literature, not the condensed one) cites only the Matthew and Luke passages. The editors of the NPNF volume of Chysostom's commentary on St. Matthew say that it is found only in those passages, and in subsequent Christian literature citing those verses. Origen, as I said, apparently (the work in which the citation is has not, to my knowledge, been translated into English) that the word was otherwise unknown -- and whatever one thinks of his funny ideas on some things, the thoroughness and carefulness of his Scriptural scholarship cannot be denied by anyone who reads his works. If he says that the word seems to have been coined by Christ or his apostles (I suppose depending on whether Christ ever taught them the prayer in Greek or not), then I think it is pretty safe to say that it was a brand-new word.
"That being said, there still remains NOTHING that supports this as the Eucharist. You are reading far more into this then what is there simply to boaster a flawed doctrine."
Well, as you know, I agree that the plain meaning of the word seems to have been "daily" and/or "necessary/sufficient," referring to the physical needs of daily life, and emphasizing that we shouldn't ask for more than what we need for the day at hand. So I would agree with you that to call it 'supersubstantial' bread would be very misleading for a 21st century English speaker. Even St. Augustine's commentaries go straight to a "daily" or "day by day" discussion, so he didn't seem to imply that even this Latin word was an obvious and plain reference to the Eucharist.
But enough Fathers have discussed it as a secondary or tertiary deeper meaning along with the plain meaning that I think it a gross overstatement to say that there is nothing that supports Alex's preferred reading. (I must note St. Cyprian and St. John Cassian go straight to the Eucharist, and only the Eucharist, but the passages are brief, and they are emphasizing spiritual meanings throughout the works in which these are found.)
We must ponder on the fact that this, again, is a specially coined word, or at least a very carefully chosen rare word. That alone should indicate that like so much of Scripture, there may be deep and layered meanings, or that at the least there are subtle shades of meaning intended.
And as the resident Reformed Christian who likes to trace your tradition through certain of the Western Fathers, I would think that the fact that St. Augustine considers it to refer in part to a daily reception of communion should mean something to you.
Even more so since the word "semeron" is also used in the same phrase. "Send me today my daily newspaper" is a strange way to ask.
Trust-but verify... :O)
Actually I do believe you're correct about its rare usage. There is a very detailed answer at Blue Letter Bible using Thayer's Lexicon. I would post the explanation here but I'm unable to due to the various Greek and Hebrew fonts.
In essence, Thayer's Lexicon states that Origin testifies that the word was rarely used in ordinary speech. Thayer also insinuates that Jerome used a poor term when he translated it as "supersubstantial bread". The derived word that Jerome, Origin and other early church fathers used was "ousias". (Forgive me if I've miswrote this as my Greek is rusty.) "Ousias", according to Thayer, is generally used in philosophical language and was rarely used. The term meant "to substain life".
Others argued this word was the poorly translated. They believe that "epiusios" should have been derived from another word "epeivai" and means the bread suffices. They compare this to Proverbs 30:8. This explanation was a bit technical for me but suffice it to say there are objections to this translation as well.
Thayer believe others have rightfully translated this against other words too lengthy to post here but I would refer you to the above definition. I am also too rusty on Greek to adequately translate it (I'd probably would interpose a "u" for a "n" and we'll be the next 100 posts arguing about my error.) However the term means "food sufficing from one day to the next".
While Thayer believes there is sufficent historical and grammatical evidence to interpret it this way, he rightfully points to the rest of Matthew to put this in context. Our Lord Jesus, once done reciting the Lord's Prayer, pointedly remind the disciples that they should not be anxious about tomorrow (what they should eat or drink) but instead concentrate on today. God will take care of our needs. He reiterates "give us this day our daily bread".
As you pointed out, not all the fathers bought into the interpretation of 'supersubstantial' bread. The historical evidence shows that the word probably was translated poorly. Finally, the context of the rest of Matthew 6 appears to support the argument that this was simply talking about daily substanance. Given all this evidence I continue to believe this was a mistranslation and some of the fathers were wrong on their interpretation (perhaps through no fault of their own).
Besides, if you want to interpret this as the Eucharist is to be administered daily then perhaps the Church should use Pez dispensers. ;O)