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:

http://dist.codehaus.org/x10/x10dt/2.0/releases/x10dt-2.0.6-win32.win32.x86.zip

(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 http://dist.codehaus.org/x10/x10dt/2.0/cygwin/)