Whether this will be implemented any time soon, or ever, is an open question, but several months ago we had some good discussions on ##textmate about how to make the most incredible indented softwrap the world has ever seen.
IMHO any kind of soft-wrap indent would be better than nothing. Everyone of us has a dream of superb incredible indented soft-wrap, but still something as simple as "last line indention" or "last line + one indention" (this is my favorite) would make us all much happier anyway.
Cheers,