PAUL100 wrote:

....

There is no standard sizes on insulated glass windows. They will make any size
you want on the 16th of an inch. you also need to know the thickness of the
unit. Usually this runs anywhere from 3/8" to 1". getting lowe and argon gas
will be easy. Trying to find Krypton might be hard since not a lot of companys
are using it yet.

Handling the extra thickness will probably by the most challenging
portion of making them. You'll have to start w/ 1-3/4 stock rather than
1-1/8 and most window sash cutter sets aren't designed for a rabbet
deeper than standard single glaze. This can be compensated for, but
will take a little extra initial set up.