I used an emulator to do this.
I had this idea and started playing 2 warriors simultaneously on keyboard. I have a tough time getting used to this.
For menuing and item management I wrote all key-bindings for both characters on a piece of paper.
So far I mainly did character movement and monster fighting though.
2 rogues would make more sense by the way.
Warrior & rogue would make an interesting couple.
If you have working controllers you can use 1 controller in each hand, which is easier.
If you want to expand your experience, this might be a good idea and I am sure, there is someone out there who will be able to enjoy this more than I do so I want to share the idea.