Logitech's keyboards have all offered built in USB 1.1 ports up until the G19 came out last year. With USB 3.0 just now coming out on the new mobos, I would expect this to take a few more years for keyboards to have it.
Id be interested as well if someone finds a keyboard with usb3 on it. Hope Logitech doesnt make a re brand g510, as that has NO usb on it at all unlike the older g15's. if the also improved the back-lighting ( cant see keys lit up well at an angle ( aka normal desk sitting mode, almost have to be standing directly over it to see some keys in the dark ) on the g510 + usb3 would be a keyboard i go for right away.