A fairly accurate treatment of Excalibur for the 4E system - perfect if you're planning an Arthurian campaign, or relatively easy enough to file the serial number off of for use in a high fantasy setting.

The mechanics seem to capture Excalibur well enough, but it doesn't seem to have much applicability to a typical fantasy campaign. I'm hard pressed to envision how to use it properly in a campaign that has no Britons or British Isles.