Anyone seen anything like this?

[Crispianus]

It certainly isn't a shoe, they are copper-alloy not iron, and have no evidence of use-wear. A vambrace would be more likely (yes, I know, standing Roman re-enactors joke). The Roman association is not especially reliable, it is a dealer that provided the group, I imagine the context is not secure, to say the least.  

The studs seem unusual to me, I am more familiar with hardware of this nature having posts which are peened over, but these are folded over like the leather jacket I had in the late '70's.

The Batavian chamfron is interesting. Any idea what kind of studs were on that?

See Chamfron no1 from Vindolanda, all the studs are gone but clear impressions were left for single post studs, on the smaller ones at least the posts have been folded flush leaving a stitch like impression the same as on yours, but obviously as singles, larger studs were bell capped.

Also see: http://nms.scran.ac.uk/database/record.p...-103-288-C see "A Roman Frontier Post and its People" Curle 1911 for details.

Sources: "The Vindolanda Chamfrons and Misc items of Leather Horse Gear" C. Van Driiel-Murray in "Roman Military Equipment, The Sources of Evidence" Bar476 pg281-318. 1989.
And
"The Leatherwork" C. Van Driel-Murray in "Vindolanda Vol III, The Early Wooden Forts" 1993.