Yes, it is in our ToDo list, however I cannot tell if we will be able to implement it. The problem here comes from the fact that we don't have access to the MOSS libraries with these hyperlinks.
For the other dialogs - Image Manager, Document Manager etc, we are browsing files in the MOSS resource galleries to which we have access, however, when it comes to hyperlinks, we are restricted to the MOSS Hyperlink Manager which unfortunately doesn't work under Firefox.
Of course if in the future the MOSS hyperlink manager is available under Firefox, we will change our own link manager and add hyperlink browsing, but for now we cannot tell when this will happen.
the Telerik team