I am. I've been working on it for 5 months now.
I got a tip too: If you want more hidden characters, this is what you do.
1. Take a character's 2nd or 3rd costume ( or both )
2. Change the costumes to make it look like another character.
3. Uhh, that's it.
Because of that, I got almost like, 40 characters.
Look at this list (VERY long, I tell ya):
--------------------------
Gerald
Cycloid Beta
SpongeBob
Evil Betty
Elder God
Freeman
Weird Al
Porc
Flance
Combot
Tommy Pickles
Keef
Doctrine Dark
Privacy (A totally censored fighter)
Gir
Stickman
Mavado
Patrick
Mokujin
Me!
Tekken 4 practice sparring partner (the totally white model)
Squidward
Cycloid Gamma
She-Bot
Command list
Nobody
Scooter
Jonathan (madeup Street Fighter character)
Plankton
Cheesearo (orange ninja)
Homer
Mokap
My sister
My sister's friend
Sonya
My hamster
Souledge
Xaiver Pendragon
Musclebob
Meat
-------------------------------
What do you think?