I am not understanding the question, if you order glass it is cut to what you want, not a special order. whither standered size or not, its all milled to the specks you request.
you bet, but cost you, they will charge by SQ foot, and delivery. same as any size pane, not a charge for having it milled at those specks.
Not sure about 1/2 inch, but 1/4 and 3/8 inch are fairly available in lengths up to 120-130 inches as the panes are produced in something like 120x84 to 130x84 (depending on the manufacturer) then cut down. Some local shops may have it readily available, others will order it from their suppliers cut to size. I'm thinking half inch may be shorter. I was just at a glass shop inquiring about 3/8 inch yesterday so I know the 130 was available. In some small or remote towns it might take an act of congress to get a sheet that size.
Not sure about 1/2 inch, but 1/4 and 3/8 inch are fairly available in lengths up to 120-130 inches as the panes are produced in something like 120x84 to 130x84 (depending on the manufacturer) then cut down. Some local shops may have it readily available, others will order it from their suppliers cut to size. I'm thinking half inch may be shorter. I was just at a glass shop inquiring about 3/8 inch yesterday so I know the 130 was available. In some small or remote towns it might take an act of congress to get a sheet that size.