This is also quite common in African-American Vernacular English, sometimes called Ebonics. This is pretty controversial an' I ain't gonna comment on it (unless provoked, maybe ), except to provide you with an example and some links:

I think the be form establishes long-term as in:

"she staying" = temporary or immediate: she's staying there at the moment.

"she be staying": she lives (in that neighborhood)

the origin of the Ebonics issue:
http://www.linguistlist.org/topics/ebonics/ebonics-res1.html

a discussion of it:
http://www.stanford.edu/~rickford/ebonics/LingAnthro1.html