The Bread of the Last Supper...

[Luke950]

So then why would Christ have used unleavened bread ~48 hours before passover?

Because God ordained that unleavened bread be used. The Jews still use it today.

Ever tried to "dip a sop" with unleavened bread? It breaks and is not very useful at all.

Well, no. I first bought some Yehuda Matzos a couple of months ago, and actually they are more like crackers. I showed them to my Pastor and explained their significance. He immediately adopted their use for Communion.

 

[icxn]

Because God ordained that unleavened bread be used. The Jews still use it today.

Actually the opposite. They were not allowed to use unleavened bread until after the trumpeting on the 14th day which that year fell on Saturday and as you correctly pointed out starts the evening of the previous day, in this case Friday. But the Last Supper took place on Thursday. (cf. St. Athanasios the Great, De Azymis)