There was this artist called Jimmy Breen who posted his work he did for the latest fanclub shirt and button set on Cargo (as seen over here). I took a look at the dates on the Cargo listing and noticed that he posted them to that site on October 8th (PFC shirt) and October 27th (PFC pin set). They were posted to that site months before the PFC revealed them in early February.
Cargo search for Paramore- cargocollective.com/search/Paramore
I saw that there was some other shirts he posted to that site (which links back to his own site) on there too. Theres several shirts that I haven't seen on Hot Topic's site, the dot net store or back a few months here in the community. Like this one...
I don't know if any of these are in Hot Topics or not seeing how it's been a long time since I stepped into one and I didn't really get over to the merch table at the only Paramore concert I went to. Some of these could be rejects and maybe some of these might be released in the near future, I dunno. His page also posted the rejected pfc pin and shirt designs on there too (he has multiple items in alot of his tabs in case you were looking for them).
But anyways, you can check out those designs at jimmybreen.com