How? And how much work would that be vs right now.

Continuation: Actually, I thought more about it, and I might have some possible solutions. It would probably change how the game works, though.

If unique players were separate processes altogether and they communicated with the server, then the game could support a plethora of languages because it could run each player as a separate process and link to it.

This seems incredibly dangerous for the server (running rogue programs), and annoying for players ("oh, sorry, your particular language isn't supported :/" or "oh sorry, the most recent version of your language isn't supported, even though you're using brand-new feature X"), but possible.

"gr1d.org supports agents written using .NET on any available platform, in any available .NET language."

I've only use the c# variant of .net, but i'm under the impression that the framework itself is extremely language agnostic: http://en.wikipedia.org/wiki/List_of_CLI_languages

.Net is run inside a virtual machine, akin to the JVM. As long as you can compile down to the bytecode language (CIL), then you can input whatever language you want.

In fact, I believe you should be able to use Mono to develop for this using a fully-OSS stack. (I could be wrong)

Such as...?