Did the label say Kaufman Kona? Kona Bay is a different company.
Moda Bella solids are very nice and come in a wide variety of colors. You can see some of them at
http://www.fabric.com
For black, I like Michael Miller's Jet Black the best of all the ones I have tried.
Edit: I wanted to add that if you think you will be using lots of solids, it's a good idea to invest in the color cards for the different lines. Shop around online, though, as they are often priced differently on different websites. (Also check the number of colors on the card to make sure you are getting the most recent.)