I know it must look like I'm on a MaRo kick lately, but he's really one of the only people doing anything interesting right now because everyone else is concentrating on preparing for the GP this weekend. Today he wrote an article about the third set from the "un" block that never was.
It is a follow up to this article which he wrote last year and you might want to give it a read first.
He posted some artwork never before seen, discussed concepts for the set and generally made me really upset that we never got a third "un" set. Could we get one in the future? It's possible and as sexy as the full art lands are in Unglued and Unhinged, I imagine the sets would sell well. It would be like having another Conspiracy - fun to draft, good cards for cube and valuable cards in every pack.
Give the article a read - it's worth it. The design process has always fascinated me and this gives a really telling peek behind the curtain.