*Mandating export of an item (perhaps based on trade agreements with the outpost liaison, so doesn't have to be something the mayor likes)
"You heard the man, Broker. 250% of their value for stone flutes. Now get to it. Tell the manager to set them on repeat, too! WE MUST HAVE FLUTES!"
I like this one.
*Mandating production of food/drink the mayor likes (within reason - a mandate for whale roasts in the middle of a desert would be a fast ticket to the magma sea)
Seems like with the amount of food types, and unproducable foods (I DEMAND FLY BRAIN STEW!!!) maybe this isn't such a good idea.
*Mandating the construction of extra furniture in the mayor's room, out of materials he likes (I have heard of this happening already but never seen it)
Happens already, seen it myself. They mandate a chair then start getting pissed off it you put it anywhere but their bedroom. I think it has to do with [SLEEP_PRETENTION]
*Mandating weapons and/or armour production if a lot of dwarves are dying from hostile action
Since when do nobles even seem to NOTICE the rabble? I doubt they'd mandate anything military except "unhand me! guards! kill this peasant!"
*Mandating import of an item that a friendly civ can make and the fort cannot - like turbans or arrows (would need more caravan arc work so that it can be ensured the caravan actually turns up with them)
Dwarves are producers, not consumers (except if you mean alcohol).