Just a thought.
To add an extra dimension to NPC characters, why not allow Elder Scrolls fans to submit their voice for use in the game?
Provide us with a short script of responses to read as well as instructions detailing rudimentary equipment necessary to produce useful sound bytes for you.
Sift through the submissions at your leisure - make use of the bytes from the good voice talent and shelf / discard the rest. Find a set of responses you like? Contact that fan for more script reading. All would be voluntary submission - no payment necessary. I'm sure there are a lot of likeminded RP'ers and other talented individuals that would jump at the chance to voice an NPC. I know I would.
If it works out, you've got a diverse collection of voice material for free and a new level of connection with your fan base. If it doesn't, you've got a lot of junk mail and an email account to delete.