They'd need a trustee living in US to handle the campaign money, unless Kickstarter has changed this recently.
I know some European game studios have used Kickstarter, but they all have had reliable contacts in the states.
Anyone in the US, the UK, Canada, Australia, New Zealand, the Netherlands, Sweden, Denmark, Norway, Ireland, Germany, France, Spain, Italy, Austria, Belgium, Luxembourg, or Switzerland can start a project. (c/p from kickstarter)