I have planned a multilingual site, based on SharePoint 2010 platform. I started a research in this direction. It's easy to make multilingual UI. Variation feature will help me to redirect users to the current user language.
The first problem is content translation. Variation feature can help me only with pages library of infrastructure publishing. Content deployment doesn’t allow editing (translating) the content.
The second problem is structure. Both sites must have the same structures. Then I insert some field in the list or node in navigation and must be realized in both sites.
The third problem is styling. Masterpage, xslt, css and others must be the same too.
I'm sure I can solve these problems after some time. I'm sure someone has already resolved this problem and tried to find the best practices for making multilingual SharePoint site.