Okay, I still haven't figured it out, but I have taken a couple
pictures:

1. This is the sloped wall I'm dealing with, from the floor
http://img.photobucket.com/albums/v3...lfromfloor.jpg
and head on
http://img.photobucket.com/albums/v3...angledwall.jpg

2. Here is one of the test crown cuts I made. It more or less follows
the slope of the wall (only the right side matters here, the left side
of the crown was cut for another test piece!)
http://img.photobucket.com/albums/v3...77/testcut.jpg

3. Here is the test piece from the end. It goes back to the wall at 45
degrees.
http://img.photobucket.com/albums/v3.../fromfront.jpg

I need to make a return to finish off that end, but it also needs to
follow the slope of the wall. I'm not trying to wrap around the
corner. The ceiling is flat. (Well, its a little bumpy, but its
*supposed* to be flat.)

Does this clarify the situation? Any new suggestions? Thanks!