Don't think you'll get what you want in one device..
you can get USB adapters for video output
http://www.cooldrives.com/usb-hdmi-adapter-dvi .html
And you can get usb video capture devices
http://www.amazon.co.uk/s/ref=nb_ss_?url=searc h-alias%3Daps&field-keywords=usb+video+capture &x=0&y=0
but pretty sure not a all one one.
Now that said, if you are serious about capturing or outputing video in high quality then USB is not the way to do it. as USB really doesn't have a high enough speed to deal with video. (USB2 is about 60MB/s PCIe is upto 1GB/s)
Your best bet would be to get a internal capture card and change your main video card to one with the outputs you need already on it.
(oh and if you plan on trying to do anything with HD video your hard drive probably wont be fast enough!!)