Hm, well I'm not going to try and divine the source of your woes here since I'm obviously a stranger who has little context about your life and can only offer broad, general advice, but I will leave you with two thoughts:
> I interview well and am quite easy to deal with on an interpersonal level.
I think most of us know when an interview goes really poorly, but my personal stance towards most interviews is that if I wasn't offered a position after an interview it's because I didn't interview well enough.
Now it may be the case that they had some ridiculous or completely arbitrary standards for the interview, and I may be fine with the fact that the interview didn't go well, but I wouldn't necessarily say I interviewed well if I wasn't offered the position.
I say 'most' because that might happen (I interviewed amazingly well and they didn't pick me for some stupid reason) once or twice, but if it's a consistent pattern than I would start looking at the common denominator.
> It has much less to do with 'me' than it does with a combination of my geographical location, and being a semi-self employed consultant/contractor/whatever they call it anymore, as opposed to having had a regular day job for the last few years.
Again I can't speak for your personal situation or pretend to understand, so take this with a huge grain of salt, but my experience with professional employment (even outside of tech) has been that these are things many companies are willing to overlook for the right candidate.
If it was something they were truly unwilling to budge on, they wouldn't have wasted the time to interview you. You would've been screened out before anyone even picked up the phone to talk to you.