Wind Trader Emeritus
All trainers now train all ranks**. So while the only Inscription trainers in Pandaria may be somewhat inaccessible, there's nothing to stop anyone training in Stormwind, Orgrimmar, Dalaran, etc.
There is a library in the dungeon - it's the south (right-side on entering) wing. As with many MoP dungeons, there are solo quest-lines through the instance space, but these only allow players to visit the pre-dungeon instance once, and the things seen there are normally different to regular dungeons.
There are various buildings outside the dungeon itself, notably on the lower south side. At least one of which contains an NPC with an inscription reference in their title (but like most NPCs, no new wares). Note that the database sites are missing many NPCs (and items) that can be seen in-game, so don't assume something isn't, just because it isn't on a database yet.
Having essential trainers in dungeons is not unprecedented - Enchanting used to require a visit to Uldaman just to level past 225 (I think). But that's a part of classic-era WoW I'd be very surprised to see return.
Added: ** A caveat on cooking: Only the trainers at Halfhill Market (Valley of the Four Winds) train cooking specializations, and only specialization dishes will take you to 600 cooking skill. There are no equivalent specializations for Inscription. But these are early days - there's nothing implemented (in-game) in Inscription yet, aside from the new rank.
Last edited by Elen; May 16th, 2012 at 12:12 PM.