Usually, for a hard intermittent stall without any other symptoms (no stumbling or rough running, happens during cruise) ...
...If the car stumbles before dying, that could indicate the fuel bowls running dry, but that's kind of a weird problem since you have a new fuel pump and you can see your filter. Is it possible that you've got a second filter in your system that's clogged?
...Or perhaps your fuel pickup in the tank is all rotted? If it's rusted through, that could explain picking up some air. However, unless it's clogged the fuel line with rust and crud, even a 'lot of bubbles' in your fuel delivery would not cause your carb any trouble.
My money's with junk/rust in your fuel tank. As the engine runs, the rust particulate will be sucked up into a filter or around the fuel intake in the tank (especially if there is a sock or screen around the intake, eventually clogging enough to stop adequate fuel delivery.
It also accounts for the bubbles -- the vacuum is having to suck harder and harder and will make bubbles when it pulls too hard.
When the engine stops and the vacuum ends, the particles fall back away from clogging the lines; when you re-start the car, you'll be able to drive a short distance until the filter or intake get re-clogged.
I had this happen to me with several of my old cars. In fact, this happened to an old Jag when I was about 20 miles from home. Every time I was ready to call a tow truck, the car would start back up and i could drive a short distance.
With each re-start, the car progressively travelled less and less distance.
Sounds exactly as you described.
Pulled the tank and acid washed it and coated the insides with RedKote -- believe it or not, it's a very easy DIY job for about $100 over 2 days (have to pause between steps)(I can describe how to do it if you find it cheaper than buying a new tank).