The 360 is heavy duty and is reported to have over 2000 stitches per minute. It has the extra strength motor compared to the 320, and I think it's all metal geared. Don't expect top speeds until it is tentatively cleaned, oiled and run in again. You have to check these and closely related models individually, since there are a few variations on machines with the exact same model number. I think the 260 has the extra strong motor too.
"Heavy duty" is a relative term too, have in mind that these are domestic models. "Heavy duty" in industrial terms are in a different leauge. I lean towards 360 being the stronger, I assume the 362 is the flat bed version.
1222 is a very late 60s model, and was made well into the 70s. It has quite a few plastic parts. The advantages with the 1222 are mostly the stitch selection from my point of view. It can be more work to get it serviced and repaired compared to an all metal model with out the more fancy electronical parts.
If you want something more heavy duty in the domestic range, I guess it would be a Pfaff 30. Its' a cast iron straight stitcher. This model often has a stronger motor than the standard of the time. I don't think the later zigzaggers are quite as sturdy as the old straigth stitch models, maybe the 130 is. Some 130s have a few simple zigzag patterns. I would take a second look at a Necchi BU if it turned up too.
For the decorative stitches, it all depends upon what you are looking for. The 1222 has stretchy stitches, but I'm not sure of the pattern selection. They might be more utility stitches, compared to other models.
I don't think you can get the optimal points of all your requirements in one machine. I'm pretty sure a Pfaff 30 stands up to everything you can fit under the presser foot, even when you push it. I think the 360 has single layer cams with out back stitching movment. An Elna Supermatic is not all metal, but still a tough machine and quite speedy. The advantage is the double layer cams and lots of decorative stitches. Another advantage with a Supermatic is the larger needle size capacity, the same as the cast iron straight stitchers. It's easier to clean and fix it than a 1222.
My speedy machines are 1000 to 1500 spm, but I don't floor the pedal when sewing. They are speedier than most coputerised machines I've used. A Viking/Husqvarna 19 and 21 are quite speedy, and have an extra gear; slower but more punch in the needle. It has a few utility stitches.
Pushing a domestic machine to it's limit can work fine, but I think you have to go for two different models and choose carefully for the jobs you need them to do. The old machines adjust to various thread weights easier than later models. All the 50s machines I have seen take top stitch thread with out fuzz. My 1960s Bernina can handle it, but its easier when I use a bobbin case made for thicker threads. It was a bit expensive and extra accessory bought separately. A Pfaff 30 or 360 would adjust with out much fuzz.