OK, first off Ash, you need to narrow the scope for what you need the server for, Vs the want.
Then you need to factor and build in logistics, IF your planning on moving this between countries there is a lot to bring into it.
First off, the state's uses different voltage/power standard than we do, how are you going to get around this? You could build in a switching/sensing UPS so that all you would need to worry about would be the wall socket, down side would be weight.
Second, have you checked US policy on bringing in data/digital media through via the airport? last time i heard they were able to seize forms of digital media if it breeched copyright etc, not sure if this is still happening, but an electronic box coming over in plane cargo... bit suss...
So if that's the case are you going to build it over there, or ship it independent? What are your COSTS associated with freight? r are you planning on carrying it onboard with you? (see BOX ON A PLANE)
If its a test model for a future product, who are you aiming at? you say consumer, but what kind of person who has server grade knowledge would be willing to carry around one with them, when its easy enough to host it up on cloud storage? ALSO Privacy/security? sates is leagues ahead of us for wardriving etc.
B) is an interesting point, needs more explaining.
If your working with data from home, why wouldnt you have it set the other way around and have the server hosted this side and then terminal or dial in when you get state's side... also work that requires a server? need more info bro.
File serving on holiday makes sense if your looking to transfer happy snaps and video etc, the 3g/4g/wifi also makes sense with this regard, but your going to have to source this equipment over there or find a device that supports the radio networks for both the states and Aus, and change them to suit the country your in. But it would mean a LOT of happy snaps and video to really benefit from having such a server with you...
These are a few things I can foresee being an issue, I think you need to invest in some time with regard to feasibility of this Vs paid server/cloud storage, or server rental. If your looking at making it a product, its going to have to be cost to manufacture vs environmental impact vs production.
Where are you looking at going in the states and when? if you dont mind me asking?