This is completely and disgustingly long. You have been warned.
So, I was thinking about how magic might be introduced for the dwarves at some future date. It'd be a cool thing to have around, and a mark of status for someone to be able to say that they support a small but thriving community of Spelldwarves.
While introducing magic opens up a lot of cool and insane ideas, because it basically strips away the need for realism and lets you do whatever you damn well please, it is important to not overshadow the more mundane aspects of dwarfy life completely, not to mention the distant "Run a Wizard's Tower" mode.
So, here's my idea. Introduce the following:
New Buildings -
(Wizard's) Sanctum, Book Binder, Library
New Skills -
Wizarding, Papermaking, Book Binding
Now, an explanation of each, in an order that makes sense to me.
Papermaking: I am calling it one skill but I can see three ways to make this. One unit of some plant -> papyrus
One unit of skin -> Parchment
One log -> Stack of papers
Now, I can see these three being done at the resource-relevant workshop (minus carpenter for the log), but it might be better to move them all into one central workshop, perhaps the...
Book Binder: Wherein books could be created. They would be blank books for future use by spelldwarfs and other folks.
What could books be used for?
Wizards could make them into spellbooks, which will be detailed later.
Dwarves of Legendary skill may be compelled to write How-To manuals, the reading of which by other dwarves could increase their rate of skill-up in the relevant skill.
Nobles and other accomplished dwarves may feel compelled to write memoirs, histories, legends, and fiction which could be read by dwarves on break to increase happiness.
Possible replacement for this when the dwarves become more technologically advanced: Printing Press, for mass production.
Library: This is where all books made are stored. This could be a small, standing-room only place, or a sprawling area with tables and chairs so dwarves can sit down and read.
How-to manuals for the faster skill-ups, other things for pleasure, and spelldwarves could get research done here.
When the economy kicks in, books could be sold, but again, always keeping one copy on hand so more could be made from it.
Now, on to wizards. I see dwarves as having a limited sphere of magic available to them, tied strongly to earth and maybe just a little booze. Anyway, for any wizards to be had, you would have to have a Wizard's Sanctum.
I see this as being a room defined from an object rather than a workshop. Perhaps a stone/wood/metal bookstand? Anyway, once you have a sanctum and whatever other requirements seem like a good idea, you will attract a new noble: The Archmage (or high wizard, or Grand Thaumaturgical Dwarfish Poobah, etc.)
The Archmage will, once (s)he settles in, begin creating a spellbook and then searching for 1-2 dwarves with latent magical talent to train as apprentices. The number of apprentices might be increased depending on how grand and secluded the Archmage's rooms are.
Once the apprentices finish training (read: reach a specific level of wizarding skill) they are full on wizards and will want their own sanctums and spellbooks, and can take on apprentices. The total number of allowed wizards will have to be some function of total dwarf population, lest magic spread among you like a virus.
Because wizards won't do work. They're as bad as nobles, if not worse. The only commands they respond to are magic-related.
Wizards will eat, sleep, lounge around, study in their sanctum/research in the library to increase their wizarding skill, and do the most important thing: Wander.
I see spell research as happening similarly to research in the game Evil Genius. They will wander your fortress until something catches their eye. It will inspire them to create a new spell, which will give a healthy boost to wizarding ability. Once the spell is created, they will know it, and it will be copied and sent to the library for dispersal among the wizarding population.
So, something like...
Wizard noticed a stonefall trap. "SWEET BEARDED GOD OF ALE! I COULD PROBABLY CREATE A SPELL THAT DID THAT!" or saw lots of sad dwarves and came up with an enchantment to put on wells that boosted their joy, or on viewing a fire imp sodomizing your defense force is inspired to create a fireball spell.
Spells could be classed in two general categories - the kind that your wizards use on their own in day to day life (fireballs for self-defense, levitation to float over rivers and caverns, etc.) and the kind that they'll do on command (enchantments, grand ensorcellments, etc.)
Large rituals would require specific numbers of wizards, with a certain number being of set skill level.
This also would open the door for magical threats with magical solutions.
Example: A Demon besieges your fortress with a batallion of Hell's finest, and you have to hold them off until your wizards can come up with a randomly researched solution (Vanquish in combat? Banish to hell? Bind into the soul of a newborn child and made to slumber, creating a freakish super-dwarf that will kill you all if and when it snaps? Maybe just prolong the inevitable by placing anti-demon wards and magical traps?)
I'm tired of writing now. I'm also tired of making it look like I'm working in the office while writing all of this. Feedback? :p