Multi-user/Multi-language environment

I think I'm probably trying to accomplish too many things at once, but here goes...

I'm running Windows Server 2003 x64 beta at home (along with XP Pro x64 beta, XP Pro win32, and a few others, but I like 2k3 x64 the best).  What I'd like to do is create a separate user account(s) that has Esperanto as the default OS-wide language.  I don't really care if everything is still in English, I'd just like the settings to be for "eo" instead of "en-US".  I'm trying to learn the language and I figured that a good way to learn would be to translate some apps.  I'll be starting with some Firefox extensions since they will most likely be the easiest. 

It'd be nice if I could have different DPIs for the accounts as well (120 and 96), but I don't think that's possible. 

(Once I finish a few extensions I'm going to try to compile a few things for x64 as well, but that is a whole other discussion on its own.)

[EDIT] I should also mention that I know that certain distros of linux support Esperanto, and that there already is 64-bit Firefox for Linux but I really want to stick with Windows on this one.