The Cutting Room Floor, otherwise known as TCRF, has unearthed two audio files hidden in the patch for Nintendo's first wave of DLC in Super Smash Bros. for Nintendo 3DS.
Alongside themes for Roy from Fire Emblem and Lucas from Mother 3, who was confirmed as a playable character in the latest Nintendo Direct, Ryu's signature stage theme from Street Fighter II as well as the general losing tune from Street Fighter II has been found in the data.
As unofficial as this may be, could Ryu be one more Capcom character who will join the roster? If so, he will likely throw hadoukens as projectiles, use his uppercut to reach ledges, and dish out hurricane kicks for combo hits.
Some have speculated that this is evidence that the Smash Bros. voting page is a sham, but I think that if this is true, this deal with Capcom has been in the works for months and the voting page is indeed separate. I'm more surprised that they've taken the Ryu from Street Fighter II instead of IV, though the SFII music is certainly more memorable.