Can you spawn special villagers?

Just build more houses of the normal type until you get a blacksmith. The profession of a new child is random, and independent of its parents' professions.

you can use this:

/summon Villager ~ ~ ~ {Offers:{Recipes:[{maxUses:#,buy:{id:#,Count:#,Damage:#},buyB:{id:#,Count:#,Damage:#},sell:{id:#,Count:#,Damage:#}}]}}