Quit in 2009, age 28. It was not that hard financially -- I moved to southern Thailand, worked on the PhD and Gensim there. Thailand is a pretty cheap country to live actually.
I feel like I'm not helping you guys much, because my circumstances may have been unique, but the honest answer is:
Not much negotiation needed. My uni had what I'd call an "old school AI department", grounded in linguistics / semantic web and RDFs / expert systems, that type of research. I was more into statistics, Bayesian inference and vectors. The mutual impact was lukewarm, and completing my thesis remotely not an issue.
Did "PhD" pedigree help in anyway? I mean you could do your research outside academia, since your department was not helping you (in research). But I guess US PhD stipend could be considered as a good salary in Thailand.
Most programs have a year or two of coursework, then it's just research and writing. So if you're ABD ("All But Dissertation") it wouldn't be a big deal if your advisor is on board. You can do committee meetings over videochat.
I was ABD and took a job, and finished my dissertation in the evenings. I basically just had to fly back to school to defend.
