Deferring School Admissions - is it possible?

Hello all, I've got a predicament. I've been lucky enough to be admitted to a couple of top 6 schools, but am considering deferring for a year for various reasons including personal and financial reasons that arose after I applied. I haven't spoken to the schools yet, but I've heard that its very difficult to get deferrals from business schools. How hard is it really? Do you basically need to have a major illness or family emergency or something similar? Are there any schools that are more or less lenient in this regard?

And one last question. If people do get deferrals, are you prohibited from reapplying to a different school the following year? I ask because my fiance is pursuing a PhD at Stanford and I'd love to join him, but I didn't get in to GSB this year (after interview) and I'd like to try again next year if I am successful at getting a deferral at my accepted schools. But I don't want to risk losing my current acceptances so if its a problem, I'll refrain from reapplying.

Thanks in advance!