I've played Dragon Age 2 several times, and there's always a certain piece of banter I find hilarious.

The banter in question is between Fenris and Varric, discussing the name of the latter's crossbow.

• Fenris: But why Bianca? You must have named her after someone.
• Varric: Nope. Mirabelle was taken.
  

So, I thought to myself "why not make a crossbow named Mirabelle for my Warden?"
I'm aware it is actually a nod to Bioware's Jade Empire, but always found it fun to have such a nod in universe as well

The crossbow may be a bit overpowered for some, but you can always adjust the values with mods such as the Winterforge

Edit: 22 Oct. 2020
Uploaded a few new options
option 1: found during the City Elf origin, on a weapon rack in the first room after dealing with the guards in the main hall (replaces the regular crossbow on said rack)
option 2: found in Lothering Chantry in the chest behind the bookcases (the chest also contains the Bronze Symbol of Andraste gift for Leliana)

as an optional file I've also included the crossbow as a loose file for those who were using it before (do note that the item file name has been changed)

Edit: 31 August 2021
Uploaded a new version with a different model and lower starting tier (previously was tier 6 now is tier 3)
properties are still the same so it's still quite overpowered even on a lower tier
locations are still the same as well (one version in the City Elf origin and another in the Lothering Chantry)

Edit: 7 January 2022
added a new location to where to find the crossbow. This one is found during the Dwarf Commoner(Casteless) origin in the player chest inside their home in Dust town.