I've tried to get the 606 kick out of Rytm, and A4.
It's damn hard, and one of the reasons I've made packs of the Drumatix and the TT-606. They are the two machines most capable of approximating that great kick drum.
The woulderful thing about 606 samples through Rytm is you can take them farther with synth voice layering, trigless trigs on the tails, retrig, and filter envelopes. Using samples in the Rytm isn't cheating, by any means. It's half the fun!