I guess I stretched it a bit in my mind: it was actually 8 days/7 night, which was whittled down to 7 days/6 nights thanks to a buttload of snow and wind at JFK the day we were supposed to leave. Even had it been 10 days I wouldn't be likely to do try a country or even a region in 10 days, my backpacking days are over. I find you can't possibly experience a city in 3 or 4 days, it takes a week minimum just to scratch the surface. You need space to wander aimlessly and sit still, to chew properly and actually taste each bite; serendipity finds you better when you aren't trying to cram 4 or 5 things into a day.
At any rate, it was a fantastic trip. Lo and behold, within hours of arriving, in fact on the bus ride from the airport, the sight of the favelas took hold of the wife's imagination and it was she pulling me into them (via a tour, thankfully). It rained about half the days, but that was the entire reason we wanted a beach vacation ensconced in a city-- for "other stuff". I will post later photos and captions. In brief summary, we of course surveyed most of the "safe" neighborhoods, got personal guided tours of some others (walking and integrated to the extent possible, ie. not as voyeurs), toured Burle Marx's house and estate, visited Oscar Niemeyer's house from the 50s, and lucked into hiring an art history professor to take us into several un-public places in some amazing modern buildings (eg. the Brazil Health and Education Minister's personal rooftop garden at the famous building by Niemeyer/Costa/Corbusier/et al). And more caipirinhas, lounging, ogling and downright staring than I care to admit.