This (admittedly somewhat comical) powered hub does not work with the grid under El Capitan (but did work with the grid under Yosemite):
But the grid works fine with this hub (that I can’t find the AC adapter for, so it’s running purely on USB power):
http://www.belkin.com/uk/p/P-F4U040/
I can make this situation work. Would be really neato if somebody had a recommendation for a very reliable and ridiculously large USB hub similar to the Manhattan linked above. I bought that thing almost as a joke, but eventually came to realize that I really do have a large number of USB thingies I’d like to keep plugged in, so it’s less of a joke now.