The latest version of Xubuntu can be downloaded from Softpedia
Xubuntu 14.04 Alpha 2 (Trusty Tahr) is now available for download, along with its Ubuntu GNOME, Kubuntu, and Edubuntu counterparts.Ubuntu no longer has development releases, but that hasn’t stopped the official flavors from getting their Alpha out the door.
“As often expected with very early cycle releases, this release has some issues which we will be working to resolve before the final release. Notably, it is impossible to successfully use the Alpha 2 to set up an auto-resized system automatically. You will not be able to set the partition sizes,” reads the official announcement.
There are also a number of problems with the distribution, but that shouldn't stop you from trying it out. Check out the release notes for more details about this version.
Download Xubuntu 14.04 Alpha 2 (Trusty Tahr) right now from Softpedia. Remember that this is a development version and it should NOT be installed on production machines. It is intended for testing purposes only.