I have an undermount Blanco Stellar 28" stainless steel sink, with drain offset to the center rear; this was the largest sink for a 30" cabinet that I found at the time - I wanted the offset drain to maximize the storage space underneath. The product description says it requires a 33" cabinet, but it fits nicely into my 30" cabinet. I have a garbage disposal, and a soap dispenser too.

The sink is plenty big enough for cookie sheets (26" interior length!) I am very happy with it.

BTW with the offset, center drain/garbage disposal, I have room on one side for a pullout for the trash and recycling (from Rev-a-shelf), and a shallower pullout on the other side (because of piping in the rear of that side, from Target) that holds the compost pail (the small Ikea stainless steel step-open trash can), sponges, cleanser, and so forth.

I also added an Ikea Variera pullout- about 5" w 21" d 4" t -- that attached to the side wall of the cabinet, for sundries like an small extension cord, tape, tape measure. Unfortunately I don't think Ikea offers that anymore - but perhaps something similar is out there somewhere.

A 30" sink undermouints into a 30" cabinet; no problem. I don't care what the sink manufacturer says.

Joseph what do you suggest supporting the sink with? Are there special straps or clips for a farmhouse sink?

Hercules Universal Sink Harness from BB Industries or a Sink Strap or two from GranQuartz. No clips or blocking, no matter what the sink manufacturer says or provides.