I don't think anyone has been able to get any items yet from them either (if they have, they're not saying anything).
When I was an envoy I was able to get a transwarp token. I was surprised by it, because I wasn't aware of its availability - I just wanted to talk to the new ambassador that happened to be there when I visited that area once. I think the token was for K7 though, which I already had transwarp ability to go to through previous earned diplomatic ranks. The token gave three free transwarps to the station, I believe. I was almost an ambassador at that point, so by the time I used it up, I was at ambassador, and couldn't get them anymore. Haven't seen the store open since then, but I've only gone to that part of the promenade once since then, when I happened to vote once. There's no point for it really, as an ambassador, though.