The people at revit-content.com have just posted a new all-in-one window family which like most of their families I've bought at the 67% discount price, for 7 days, if you register for their mailing list.
Whatever you think of the all-in-one approach the families are very useful and at the launch price you would probably buy them anyway.
They are certainly a great service for those of us who don't use standard windows and doors in our projects (not that you would find non-North American content in Autodesk Seek anyway at present).
They did something clever with their elevator family, including details from the main manufacturers but as I never use elevators I've not tried it.
Still waiting for panelled doors in their door family but I guess that will eventually come.