Not going to give away any of the real details here, because I'm wanting what I've added to be a bit of a surprise. However, I can say it requires two outfit graphics and a sprite and needs to be at least up to Colosseum's quality. I also need a sound effect to accompany this addition, though if all else fails I might be able to get one on my own.
If those kind of things are up your alley and you want to make a quick contribution, send me a PM and I'll get you the details you'd need.
And, of course, full credit will be given.