I'm trying to port other smb hacks to the
Two Player Hack (by CorpseGrinder and Ti)
I do not take requests but I can share information on hacking the
Two Player Hack.
I've already made a Co-Op version of my own hack:
Mario's Keep.
https://www.romhacking.net/hacks/5903/Luigi's Chronicles Feat. Waluigi 
I'm finished with reworking a old hack by Googie to make it co-op.
I tried to give Waluigi a separate sprite. I have managed to do so in the original game, but I can't move my changes to the Two Player Hack, unfortunately.
I'm also working on two more co-op hacks I will post about them later:
Super Mario Bros. Co-Op Coin Challenge 