faster mirrors
https://wiki.qt.io/Online_Installer_4.x
https://download.qt.io/online/qtsdkrepository/windows_x86/root/qt/Updates.xml.mirrorlist
use the path before '/online' (no forward slash at the end)

qt-unified-windows-x86-4.0.1-1-online.exe --mirror http://ftp1.nluug.nl/languages/qt

http://mirrors.tuna.tsinghua.edu.cn/qt/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (cn, prio 100)
http://mirror.bit.edu.cn/qtproject/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (cn, prio 100)
http://mirrors.ustc.edu.cn/qtproject/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (cn, prio 100)
http://ftp.jaist.ac.jp/pub/qtproject/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (jp, prio 100)
http://ftp.yz.yamagata-u.ac.jp/pub/qtproject/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (jp, prio 100)
http://www.nic.funet.fi/pub/mirrors/download.qt-project.org/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (fi, prio 100)
http://master.qt.io/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (fi, prio 100)
http://ftp.fau.de/qtproject/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (de, prio 100)
http://ftp.acc.umu.se/mirror/qt.io/qtproject/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (se, prio 100)
http://mirrors.dotsrc.org/qtproject/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (dk, prio 100)
http://qt-mirror.dannhauer.de/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (de, prio 100)
http://ftp2.nluug.nl/languages/qt/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (nl, prio 100)
http://ftp1.nluug.nl/languages/qt/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (nl, prio 100)
http://qtproject.mirror.liquidtelecom.com/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (ke, prio 100)
http://mirrors.ukfast.co.uk/sites/qt.io/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (gb, prio 100)
http://qt.mirror.constant.com/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (us, prio 100)
http://mirror.csclub.uwaterloo.ca/qtproject/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (ca, prio 100)
http://qt.mirrors.tds.net/qt/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (us, prio 100)
http://mirrors.ocf.berkeley.edu/qt/online/qtsdkrepository/windows_x86/root/qt/Updates.xml (us, prio 100)
