One of the things that bothered me in dwarf fortress was the inability to make decent stacks of coins as stacking is not implemented yet. This could result in split stacks that would never be united again and if you like collecting a treasure hoard like me(my hut is now stacked with chests full off 500+ value items) you end up with a list of coins that spans the screen. After some experiments with building reactions that would yield the same item I managed to restack meat and after that I managed to get one that stacks coins. As far as I have tested it, making a stack 2 out of single coins works but not when I make a reaction with a higher product quantity, weirdly the reaction will not finish. (now I think of it it might need 10 unique stacks so please test that for me if you want) I did found out luckily that using the stack of 2 reaction can use much more input (as it gets stacks). When using 2 stacks of 5 I got a stack of 10 of the qurrency local to the region. I hope I can make other people happy with these reaction and if you can expand or test it further for me please do let me know.
Anyways, here are the reactions:
[REACTION:MAKE COIN STACK]
[NAME:make 100 coin stack]
[ADVENTURE_MODE_ENABLED]
[REAGENT:A:100:COIN:NONE:NONE:NONE]
[PRODUCT:100:100:GET_ITEM_DATA_FROM_REAGENT:A:NONE]
[REACTION:MAKE SMALL COIN STACK]
[NAME:make 10 coin stack]
[ADVENTURE_MODE_ENABLED]
[REAGENT:A:10:COIN:NONE:NONE:NONE]
[PRODUCT:100:10:GET_ITEM_DATA_FROM_REAGENT:A:NONE]
[REACTION:MAKE VERY SMALL COIN STACK]
[NAME:make 2 coin stack]
[ADVENTURE_MODE_ENABLED]
[REAGENT:A:2:COIN:NONE:NONE:NONE]
[PRODUCT:100:2:GET_ITEM_DATA_FROM_REAGENT:A:NONE]
[REACTION:STACK MEAT]
[NAME:stack some meat]
[ADVENTURE_MODE_ENABLED]
[REAGENT:A:2:MEAT:NONE:NONE:NONE]
[PRODUCT:100:2:GET_ITEM_DATA_FROM_REAGENT:A:NONE]
just add them in the reaction_other script in the raw/objects folder and make a new world. I do hope this helps some people as it did with me.