I'm a Service Advisor at a Honda dealer. 50K is a pretty good life expectancy out of a set of brakes on the Odyssey. The reason your van won't go through fronts twice as fast as rears is because the vehicle has been designed for the rears to apply first to counteract the forward pitch under braking.
I had one guy (really his wife) go through a set of rears at 23K. I think she was a two-footed driver. The brakes on the Odyssey are designed to be quiet and consistent, not last forever. The recommendation from Honda, called the service limit, is between 1.5-2.0 mm remaining until the wear indicator.
The reason it's not recommended to wait for the indicator is because that's when you're into the bonding material on the pads. Not very efficient braking. Also, we've seen the indicator actuall break off and people drive all the way through the pads. Yikes!
That's right about the resurfacing. If the shimmy doesn't bother you, you can just replace the pads.