What do you mean by same interface? Like the SSD has SATA connectors?
I believe you need an adapter for a SSD, although I may be incorrect.
edit: Oops, he has a laptop, nix the comment about adapters.
You could buy an PCMCIA slot USB 3 card couldn't you? Not sure about the bandwidth provided by the card slot so not sure you'll see anything near USB3. As long as you can find an SSD that has the same connector as your laptop has you should be good to go there as well.