They also had several other Avenger-themed fabrics.
Even one that includes Spiderman (from the Avengers Comics)
There's a total of five fabrics with an Avenger's theme.
I really like this one from the movie.
Unfortunately, the rest of these fabrics are also missing Black Widow from them. However, at the same time, Hawkeye is missing as well, so I can't really say that it's the lack of attention. I think they just didn't include what they consider "minor" characters. (And seriously, what's wrong with Hawkeye?!?!)
I guess one out of five fabrics isn't that bad, considering the current track record.