I am not using mugen, I am using ikemen which comes with tag.
Mugen does have a tag patch so you do not have to switch to ikemen if that's all you want.
Sorry but I would not want to resprite another Luffy. There is a new sprite based One Piece game coming out September 21,2016. I am sure people will rip the sprites and make awesome One Piece characters.
Sorry for the late response. I check my email every day and I didn't see any notification from this site expect for my private messages.
Thank you.
Here is a trailer for a sprite character I made!