Since you're retrofitting, I'm not sure but if your fabricator has any experience with counters, she can probably weld in a sink you purchase that fits the hole (once you pull out the old one) or even fabricate you one from scratch. The last stainless counter I had installed wasn't really very different from what you're doing. My GC put down the substrate and the stainless guy came in and templated. It might have well have been an old laminate counter!

Pin down the fabricator and ask if they can weld in a sink or custom fabricate one. It should be not much different from doing a job from scratch.

We did this, and pulled out the top-mounted sink to start. We also cut out a spot for an integrated drainboard. The fabricator made us a sink that is integrated as well, so we could choose the exact dimensions. That was really nice for us, as we got an insanely shallow wide sink to allow my very tall husband to easily work there.

Any fabricator worth their salt fabricates sinks regularly. They can also weld in a sink for you...it's just up to you how you want to deal with that.

Thank you so much! I love the idea of just integrating in the sink.