So, here's what I did:
Checked the int status of the Catalyst, saw it was reporting a-half, a-100
Changed the Ricoh to match that, tested printing [slow but job completed]
Changed Ricoh to auto-select, enable 1Gbps, testing printing [fast!]
Checked int status again on Catalyst, saw message on the console that the int had changed its state to "down" twice [%LINEPROTO-5-UPDOWN and %LINK-3-UPDOWN], then changed its state to up on both again
Reconnected to console, checked int status to see port reporting a-full, a-1000 now
Printing like a freaking champ at the moment
Sorry to falsely accuse the Meraki!