I have a 20 Gb Lacie Pocketdrive, it has two firewire ports and USB 2 and was quite pricey (because of the dual nature of the connections) but it's pretty fast, it does eat up the juice rather quickly when connected to a laptop running on it's battery though and I imagine this will be the same for any drive you buy.
I should think most drives come with a 'through' port of some kind because obviously they're looking for you to buy more of their drives and stack them.
Actually now that I think of it I think I remember seeing some very small adapters to connect any internal drive to a firewire cable. This thing didn't have a case so you're left with an ugly looking internal drive on the outside but it sure solves the problem of size and if you're just keeping it in a laptop bag then you're laughing.
But for the life of me I can't remember who the supplier was, they made a few different versions including a USB one and as far as i can recall it took power straight from the firewire cable and it was quite cheap. If you post an inquiry on this forum about it someones bound to know. In fact i'll do it for you!
