I find only "red wine" in the Scriptures and it seems natural to represent blood. Anyone else encountered white grape juice or wine for the Lord's Supper, or know the reason for it?
If we are allowed to change the symbols as we see fit, I vote for beer and pizza!

Seriously, this is a matter I feel rather strongly about. As Pilgrim alluded to, bread and wine, and only bread and wine are acceptable at the Lord's table.
Now as to your question, I agree with the phrase in bold (emphasis mine) in the part quoted above. But I have to ask, in all the places where the Bible refers to wine, is it specific as to red vs. white wine? Would white wine be acceptable?
And in regard to the bread, is either leavened
or unleavened bread acceptable?