Roman Full Plate Armor?

[SigniferOne]

It is generally assumed that the full-plate armor, e.g. of a medieval knight, was first invented in the Middle Ages (obviously ignoring Dendra Armor and other such items of great antiquity). Romans clearly had the technological access to a full-plate armor suit via the lorica segmentata, but they've never adopted a full-body suit as far as I know. It's precisely in this context that my interest was piqued by a passage in Tacitus:

Annals 3.43:

[Julius] Sacrovir with some armed cohorts had made himself master of Augustodunum, the capital of the tribe, with the noblest youth of Gaul, there devoting themselves to a liberal education, and with such hostages he proposed to unite in his cause their parents and kinsfolk. He also distributed among the youth arms which he had had secretly manufactured. There were forty thousand, one fifth armed like our legionaries; the rest had spears and knives and other weapons used in the chase. In addition were some slaves who were being trained for gladiators, clad after the national fashion in a complete covering of steel. They were called crupellarii, and though they were ill-adapted for inflicting wounds, they were impenetrable to them.

Do we have more information about these crupellarii?


EDIT: Oops, I have found some more things, e.g. this reconstructed suit:



Do we know some specifics about the suit's construction, and what sort of provenance and usability it had?

Do we know the reasons why the Romans never adopted the crupellarius suit militarily (e.g. for tactical reasons)?