Thank you, Paul, for sharing Judy's comments, which are very interesting.
What caught my attention was her observation about the recent Ebonics
controversy:
The resolution was
> intended for the TEACHER's benefit, to improve communication
> between teachers and students (so teachers can understand
> what the Other system is that "interferes" with the students'
> use of standard English, so that they can diagnose more
> accurately the difficulties students are having and therefore
> intervene more effectively...), and to improve students'
> attitudes/ stance toward school (which is, in my view,
>  the bottom line of literacy instruction -- getting
> students invested....)

You made a similar point in your own message:

"The other difference, of course, is that my ESL students invested
themselves with gusto in the learning process, whereas my present inner
city adolescent students would rather be almost anywhere BUT a classroom.
And their language is so "peppered" with profanities that using their
dialects as a point of departure might take a lot of creative maneuvering."

I have been looking carefully at work on teaching standard English to
African American students, including action research in my own classroom and
school (100% African American in rural Mississippi).
I suggest that what both of you are describing (and what many of us are
encountering) is not "interference" but resistance.  Many of these students
disconnect themselves from schools in general, and from English classrooms
in particular, as a form of self-defense.  "Investing" in the learning of
standard English comes at significant psychological cost to Americans from
certain ethnic groups.  Hypothetical career success is too distant a reward
for the immediate sacrifice of self and group identity. Arguments about the
necessity of standard English for social mobility are contradicted daily
experiences of well-educated adults in their communities and families.
     On the other hand, I have found many examples of teachers who
successfully teach standard English to the types of students you describe.
Their success has been attributed to the classroom context in which they
present standard English.  Some of these issues are addressed in works such
as--The DreamKeepers: Successful Teachers of African American Students, by
Gloria Ladson-Billings, or Other People's Children, by Lisa Delpit.