I wrote a few pages exploring this very issue in. The details are:
George Athas, 'The Creation of Israel: The Cosmic Proportions of the Exodus
Event'. Pages 30-59 in Exploring Exodus: Literary, Theological and
Contemporary Approaches (eds. Brian S. Rosner and Paul R. Williamson;
Nottingham: Apollos, 2008).
One of the conclusions I reach is that there is no singular phrase that
captures the multivalency of the Hebrew phrase. The closest I could come up
with is "I be who I be". It's clunky in English, but I think its the best we
can do with one phrase. I also explore some of the various issues involved
with interpreting the phrase.
Regards,
GEORGE ATHAS
Moore Theological College (Sydney, Australia)
www.moore.edu.au