Hmm...)) It was originally conceived as a joke - a guitar. But since you liked it, I'll try to incorporate your suggestions.)))
P.S. A guitar isn't a person, so I don't think it will be a big problem to create it myself.
To make a mod for April Fool's Day with just one unit – a Death Knight or a Monk with a guitar – requires a plan. What are we going to do? Replace Bards with Elementals and add a spell to summon the Bremen Town Musicians? Or create a new faction, or maybe a unit for something specific?
And we need a concrete plan: on which models will we do this? For example, there will be a defect on the Monk if we attach the guitar as in the picture; it will pass through his chest during the attack.
A Vampire could look cool wielding a guitar, and Undead even better, but they would be hitting with the neck.