Now THERE'S a great idea! Unfortunately there's a major hitch; Street Fighter IV is a period piece that, although a revision of SF2 characters with even newer characters that we are supposed to believe we'd somehow missed out on the first time, actually takes place somewhere in the mid to late 1990s. The thing that sets SF:TLY and SFR apart from SF4 is that "Later Years" and "Reunion" are the only two entities in the Street Fighter Universe that represent the characters in the present. This makes the merchandising more lucrative because it's more product specific. For instance, whether he's a game sprite, a cartoon depiction or an action figure, you know you're looking at the 45 year old Ryu when you see his longer hair with the characteristic white streak down his left side. 49 year old Guile has a beer belly and 53 year old Zangief's beard sports a white chin. Chun Li somehow remains perpetually young, LOL! Actually, Chun Li will still be a mere 41 as of March 1st but, because Ana Parsons is still only in her 20s, her portrayal of Chun Li manages to turn back the clock for her character.
Perhaps your idea would fly best as a downloadable conversion for SF4 that stands on its own when selected. What are your thoughts?
By the way, the character select image below was created by our very own forum member, Stein. Great work, Stein!
A conversion that stands on its own? You mean like an expansion pack or an add-on? That'd be cool, although it wasn't what I had in mind.

I wasn't thinking deeply, at all; I just thought having the option to replace the classic characters' 3D models with their
Later Years counterparts' would be really spiffy, like playing dress-up. They wouldn't exist separately from their young counterparts; in fact, they wouldn't really exist at all, thus avoiding a time paradox.

It'd just be a little visual promotion for
The Later Years.

(Oh, wait, how would that work for Wheelchair Bison??? Drat!

)
Alternately, maybe it would make a wicked April Fool's prank