As of version 2.0.6, X10DT is available as an all-in-one zip file that contains Eclipse, X10DT plugins and all its·prerequisites.

The X10 DT Eclipse Based Editor for Win32 with Cygwin is available here:

(Note that, as for the update site install, you still need to download the patched MPICH-2 version for Cygwin that you can install directly from setup.exe when pointing at the following location