double a-prefixing?

[Douglas Bigham]

Another random a-prefixing wierdness... last Saturday, my mother-in-law-to-be
said:
"I musta been a-gonna write on it." (describing some odd scrap of paper she
found).

It struck me (and my husband-to-be) as odd.  Now, forgive the bad syntactic
description, but I think this is the first time I've heard the a-prefix on the
"future going" rather than the "movement going".

-dsb
Douglas S. Bigham
Department of Linguistics
University of Texas - Austin
http://hometown.aol.com/capn002/myhomepage/index.html