Thanks Peter for adding to the permanent documentation. That's a big help and we don't get around to updating documentation as much as we should. The Unicode support is being developed and is currently sitting as pull requests to the develop branch of WeBWorK. We are going somewhat slowly in adding the unicode support because while the change is small it is pervasive and has a real chance of not being backward compatible. As a result we are being cautious and not trying to take any action that might raise issues that we wouldn't have the man-hours to fix quickly.
If you have the capability of temporarily trying out some of the utf8 patches and reviewing them let me know.