Could you provide information about who the plugin developers are, so that a request can be made to them instead for this feature?

Yeap. It's a wordpress plugin called WP-Cumulus, here is the website or the plugin and the author: http://www.roytanck.com/2008/03/15/wp-cumulus-released

A Wordpress plugin?

There is such thing as being evil, but that, my friend, is a special kind of evil =D

Looks like it requires some fiddling around with the source code Brunhilda:

Some characters are not showing up

Because of the way Flash handles text, only Latin characters are supported in the current version. This is due to a limitation where in order to be able to animate text fields smoothly the glyphs need to be embedded in the movie. The Flash movie's source code is available for download through Subversion. Doing so will allow you to create a version for your language. There's a text field in the root of the movie that you can use to embed more characters. If you change to another font, you'll need to edit the Tag class as well.

Source: http://wordpress.org/extend/plugins/wp-cumulus/faq/
How to add another language: http://www.roytanck.com/2008/08/04/how-to-add-more-characters-to-wp-cumulus/

I have Flash installed and can probably do this for you.

@Squark: If I recompile this with all character sets and upload it, is that enough to allow you to then implement that into Wikidot?

The only thing I'm thinking would be a problem is that the tag cloud would be significantly larger in file size will all of those character sets in there - so that might affect the loading time if they have to download the file in order to view the 3D tag cloud.

Well it does depend on what "significantly larger" actually will mean :) I believe we can do two sets of flash files, the current one and the expanded one. There can be an option in the tag cloud module that would trigger the full character table. Great idea leiger, thank you very much for that! :)