I still use vsampler. It came with Sonar a few versions back. I upgraded to the full version, and then all development stopped, but it still works so who cares ?? It plays everytype of sample imagineable, but it will never be 64 bit.
I have some old CD's with giga samples and this still plays them fine in Sonar (still)
I have Kontakt....apparently Kontakt can play giga samples but it is a lot of work and you have to know what you are doing. That disqualifies me on two counts.