I'm wondering if anyone has actually seen this [bringing in a consultant to review resumes and sit-in on interviews] occur in-practice, either in the software or other industries?
It's not uncommon, though I've only seen it first-hand once. I have several consultant friends who get called up several times a year to help an organization make initial hires in an area the organization has no expertise in.
When hiring people for specialties that neither my team nor I have any experience with, I tend to screen first for general thinking skills (see On Interviewing Candidate), then do reference checks. In Silicon Valley, you can often find someone who's worked with a candidate within a few phone calls.
