Any 92-04 Isuzu automatic will have those fittings. You can cut the lines about 3-4" from the fitting and then use hose and clamps to joint it to your existing lines. I had almost exactly the same issue on a Trooper that I had to swap the transmission in. The line snapped when I tried to back it out of the transmission.
If one insists on having steel lines, they can buy Bundy-Flex or whatever brand of replacement brake lines that their local auto part6s house carries. They are available in quite a few diameters, so you can pick and choose.
Transmission cooler HOSE is perfectly serviceable, and is used on many new vehicles from the factory near the heat exchanger and/or the transmission to keep motion from work-hardening the l,lines until the break.
EDIT: Also notice that you do NOT have stainless steel lines.