XS Community Edition/0.4/Services/Offline USB install
If the install process detects a USB key of USB drive, it stores a cached copy of the downloaded RPMs on the USB drive.
The second time the install is run, it grabs the necessary RPMs from USB key instead of downloading them.
Full offline install requires runing rpm -ivh /????/xs-install.???.rpm
The installer would need to know the path to the USB device.