External USB or Firewire DVI capture card recommendations?

Is there something like an external USB or firewire DVI capture card on the market, that can be recommended to be used with VVVV? I’d need 30FPS+ and HD resolution would also be very nice…

I tried an internal card from “Datapath” which worked fine but now need the same thing on my laptop.

This are supposed to be good, but you need the usb3: http://www.blackmagic-design.com/products/intensity/

I hused 2 internal (Intensity Pro) and them worked well…