as far as I know, no it will not work, you CAN install a usb hub, there's a tutorial, in the well...tutorials.
but to run keyboard, mouse and IR you'd need to take up 3 of the ports one for each.
i.e., I know that the IR dongle is disabled once a controller is plugged into port 4, thus if you tried plugging in a keyboard into an "extended usb" connection alos on port 4 it would disable the IR dongle, and so on
to be safe use 3 seperate ports, I'm doing the DVD IR mod, and 2 backside ports, and will end up using ports 2-3 maybe for that.
just my 2 cents