Update 27 Sept 2011: I spoke with the Hood River Sales Manager for Cardinal Glass. He said they can make a 1 3/8 inch triple pane LoE 180 unit with coatings on surface #3 and #5 instead of #2 and #5, for yet higher solar heat gain coefficient. For 95% Argon fill it would have U=0.13 Btu/h.ft2.F, SHGC=0.59, and VT=0.70.
Update 26 Sept 2011: I did find a mother lode of Canadian manufacturers on the Insulating Glass Manufacturers Alliance web site. On the Certification tab, IGMA Canada (IGMAC) has a Certified Products Directory which gives company names and some details of construction though not performance. At a glance it looks like maybe 60% are double-pane and 40% triple-pane. There are even two quadruple-pane products listed, from ECO Insulating Glass in Mississauga ON and from Northerm Windows (RAB Energy Group Inc.) of Whitehorse, YT.
This is the current state of my knowledge. Please comment if you have corrections. I know of only a few North American manufacturers of residential window glass units:
AGC Flat Glass North America
AGC Residential Glass data sheet
Formerly AFG Industries. Now a subsidiary of Asahi Glass (Japan.) Their main factories are in Tennessee, Kentucky, and Kansas. They seem to be unaware of Passive House. They have double-pane units but no triple.
Cardinal Glass Industries home page
Cardinal Glass data table
Cardinal specializes in Residential window glass. Their HQ and R&D are in Minnesota and Wisconsin. They have factories in 7 other states including Oregon. They supply double and triple pane glass to multiple window manufacturers including Milgard, Atrium, and Inline / Cascadia.
Guardian Industries home page
Guardian residential glass for North America
Guardian Europe coated lo-E glass
Guardian is based in Michigan, and their European division makes the impressive Climaguard N3 also known as Flachglas which is Passive House certified. However there is no evidence on their web sites that they are making or selling any triple pane units in North America.
PPG Industries home page
PPG Residential Glass home page
The venerable Pittsburgh, Pennsylvania glass manufacturer. They do not make multi-pane glass units themselves but they have a wide array of glass and coatings as well as a warm edge spacer. They have a Find a Window Manufacturer page which turns up 9 or so listings for Oregon & Washington. Their graphics and examples are all double-pane, BUT their window manufacturer support includes an online calculator which allows you to design a double or triple pane glass package and see what the center-of-glass U-value and SHGC would be. (Similar to what the Lawrence Berkeley Lab WINDOW software does, but limited to the PPG catalog.)
I made a triple pane with 0.60 SHGC and 0.15 U-value, see if you can do better!
Serious Windows home page
Serious Windows residential data sheets
Serious makes both their windows and their glass in Sunnyvale CA. The glass used to be called Alpen glass, and was purchased by Serious around 2008. Their technology is 1-3 layers of suspended film in between the inner and outer glass panes. These are the only North American glass manufacturers with the words “Passive House” on the their web site.