I used this one (Miky by Nameeks in the Scarabeo line) because it is 15.8 inches x 12 inches. It worked well is my 22 inch wide vanity. 6 inces deep and that is deep enough I find. The base price is for white which I got, but it looks like you can use the color "Pergamon" and double the price to about $600 (!). I really like the sink. It's Italian and for European sinks my Italian countertop installer told me the overflow is in the back under the faucet not in the front like they are in the US. This is the photo from the website....I haven't taken pix since I'm not done yet.

Here is a link that might be useful: Nameeks Scarabeo rectangular sink

I used the Kohler Archer sink, which is a rectangle with a slight curve to the front, like a very fat capital D. It costs about $90 at HD, and I don't know if it comes in any colors besides white.
WIP photo:

Decolav makes a 21" undermount that you buy from faucet direct for $65.

I have both the Kohler Kathryn and Ladena in my house. I like them both, but I do prefer the lines of the Kathryn.

My thanks to you all. I picked the archer by kohler, it was 119 for my color of biscuit. I like the curved front of the archer. It will fit my space and give me plenty of counter top. Thanks again!