The last Smash Bros. game, like the one before that, was a smorgasboard of characters. There weren't just Nintendo developed characters, but the likes of Sonic and Snake also made an appearance.
No More Heroes designer Goichi Suda is already making off-handed remarks about his desire to see NMH hero Travis Touchdown in the next Smash Bros.. Suda tells Nintendo Power:
I love him (Travis), and I want him to be a huge star. That's why I'm working very hard to make this game as interesting as possible. Maybe in the future, we can see him fighting alongside Link in the next Smash Bros. [laughs] That would be great.
Yes, yes it would.
Suda 51 wants Travis Touchdown in next Smash Bros. game [Nintendo Dpad via IncGamer]