Do you have an old one in your inventory or city? You cannot have more than 1, so they building won´t show up.
If you have not crafted any of the "unique" buildings (all sets and evolving buildings) the list of possible buildings in your MA is extremely long and the chance is very small of the one you want showing up.
By crafting all of those once (and keeping them in your inventory if you don´t want to use them) will prevent them from showing up again and therefore increase your chances of getting the one you want.
@Solanix wouldn´t that be another candidate for the Tips&tricks section? It comes through at least once a week