The latest is the Karoryfer Meat Bass with over 400 samples of Arco and Pizzicato. The Arco has every third note sampled in five velocity layers with both up and down bowing which alternate as round robins. The Pizzicato is again every third note sampled with four velocity layers and four round robins. There are also some cool percussive noises from C3 to C4 if you use the G#4 key-switch. This version is definitely more polished than the original and sounds quite good in an orchestral setting.
The earlier version is the D. Smolken Double Bass, which was created before the Karoryfer name as best I can tell. It is rougher, but has its own earthy charm. The previous Kontakt version had some problems, so I fixed it up a bit. It has some great cello 'noises' on the # key-switches.