It looks like Jesse Vincent has found a way to re-flash Kindle 2 with custom hand-made firmwares. At the moment he’s not uncovering any details of the process. Hopefully, he or somebody else would soon come up with firmware that would support full range of Unicode international characters to enable proper display of Asian, Cyrillic and other characters on web-pages and in downloaded eBooks and documents.
It took Microsoft Zune more than a year to put a Unicode font in the firmware (even considering that Zune is a Windows Mobile-based device, and Windows Mobile had proper Unicode support for ages). This is why I don’t believe we would see Unicode support in official firmware updates from Amazon and Kindle community would be better off helping themselves.