My friend and I have been working on designs for Kitty and her Kart for a while, they're all concept drawings but I haven't got them scanned in yet. I love SuperTuxKart and have been really keen to get Kitty included as soon as possible, but I'm also worried that she might not turn out looking as awesome as she should if someone without any real love for the character were to quickly whip something up to include in the game.
I've been following your thread on the FreeGameDev forums and was planning on posting the designs as soon as I can get them scanned. I really hope we can work together on this.