The vendor Lt Vacno on Galanda station says in the description she sells Mk VIII and Mk X Starship Equipment; Engines, Shields and Defectors.
She has the Mk VIII Equipment, but instead of Mk X Equip, she has Mk X consoles, the same ones another vendor in the same room has. She is the ONLY source of Mk X equipment for the PvP Medals.
Unless of course, you can afford the outragous prices in the Exchange.
This was once listed as "under investigation" on the Dev bug reports, but even as of the March 18th update on the Tribble test server this is STILL not fixed, even though it was reported as far back as the BETA version, and it is no longer listed in any of the Dev/enginnering/bug reports at all, in any category!
I strongly encourage ALL Klingons to report this bug using the in game reporting system, since obviously the Developers will not fix it unless they feel enough players have noticed to it warrent a fix.