Can someone explain to me real quick if the MX1000's reciever is that charger base but its hooked up to USB, or is the reciever just a little USB dongle like I've seen on others. I really like the MX1000, but since I'll be using it with my Powerbook, I don't want to be carrying around that big charger base as well, but I wouldn't mind the USB dongle that I've seen from other companies.