If you're tight on usb inputs then something like this Akai might be of interest as it has 3 extra usb ports built in. I have no idea if it's any good or not though, sorry. http://www.musiciansfriend.com/pro-audio/akai-professional-eie-i-o-audio-midi-interface-with-usb-hub

OR, you might want to consider a usb hub, a less expensive usb mixer without midi, and a midi usb cable.