In a word or three: I love this. It's fun, as simple or complex as you need it to be, and the twist at the end is nasty. However, I must agree with valadaar that relying on the PCs to be master architects is a pitfall. My current group is a wizard, a druid and a rogue (NPC) -- no real fodder for the plot hook to work.
It's possible for the party to answer an advertisement for the job, and then bluff their way into winning the contract. It's also possible that it could be a case of mistaken identity (the master builders weren't in court at the appointed hour, and the nervous butler ushers the PCs into the audience without asking too many questions). Or what about another contest, of sorts -- to choose the architects for the maze?
In short, I love the premise but would really like to see some more plot hooks to help bring this into an ongoing game.
Perans is indeed within his own world- although he exists in the world of the players, his magical potential has allowed himself to birth an entire small unvierse within his own head. The two men who had kidnapped Perans accidentally transported their own minds into Perans' world when they attempted to cast diagnostic spells upon him. Perans quickly obliterated the two men, seeing them as intruders into his world.
Perans has moved into an area of seclusion so that he may finish his universe in peace. He will ask the players to leave him in peace so that he may continue his work.
Should the University or the Necromancers try to stop him, Perans will drag them, and the players into his world so that he can stop their agressions.
(At which point the players have to decide on helping or hindering Perans.)