I have been active on various forums (first J-1, later NIW/EB-1, after that on CP and then I-485 forums) for last four years I believe.
Not a single poster that I remember ever said his/her NIW-based I-485 got approved without local transfer/interview. Many EB-1 got approved without interviews though.
However, a couple of reliable posters here (like GC_impatient, Gchello, and may be AG and fikabir) mentioned in past that his/her friend (or someone they knew) got approved without interview. Almost all NIW-based I-485-waiters in past, who were kind enough to post their experiences, were transferred and interviewed.
When I asked about this to various attorneys (via e-mails or through their websites), almost all replied "that's not true, transfers are random, etc.." However, if I have to conclude on my own from what posters have said on various online forums in past, I would say odds are clearly and very heavily against the approvals without interviews for NIW-based I-485 applicants.
Best wishes,
Jigesh