Below are a few links that will show you common choices of stainless steel undermount sink options. This isn't every option, but is the most common set ups. If you see a shape and size you like, let the Kitchen Gallery know. We will confirm that that size sink will fit and is appropriate for your size sink base cabinet. Then provide pricing.
A little sink jargon for you... A 50/50 sink means that the sink bowls are divided in half. A 60/40 sink means the left side of the sink is bigger than the right side of the sink. A 40/60 sink is the reverse.
BELLA -- CLICK HERE
C-TECH -- CLICK HERE
An 18 gauge stainless sink is OK... A 16 gauge sink is better... 16 gauge sinks are thicker and have more steal than an 18 gauge sink.
Most of the sinks will come with some nice accessories, particularly the protective grid that sits at the bottom of your sink. This helps protect the sink from dings and/or scratches.
Suggested Reading -- COMMON UNDERMOUNT SINK OPTIONS