I dont think the San Hedron wore gold silk brocade, but it seems our Lord did warn agianst those who enjoyed making long prayers and making their phylacteries broad to recieve their reward before men.
The Sanhedrin was a law court. They did not have explicitly ecclesiastic function. Since Jewish jurisprudence did not distinguish between what we would call "canon" law vs. other law, the Sanhedrin would be associated with the Temple hierarchy.
As for the warning against long prayers and enormous phylacteries, these applied not to the Liturgical acts of priests but to things expected of all Jewish men. All were expected to pray regularly (like Orthodox Christians), and there was an appreciation for beauty in prayer (like among Orthodox Christians). However, in addition, Jewish men were expected to wear the tefillin when they prayed (at least). The tefillin contained scrolls with Deutoronomy 6:4-9 and 11:13-21 (two scrolls) and Exodus 13:1-16 (split into two scrolls). This, again, was not a garment specific to the priests. It was the practice of that day for some Jews to make a big show of their piety, reciting enormously long prayers and wearing very large tefillin--like some Christians today recite enormously long prayers and take great pride in demanding that women wear floor-length skirts at all times. Our Lord was not denouncing priestly vestments. He was denouncing people who turned piety into a public spectacle of one-upmanship.