Mike is right, you would need a D-Star capable radio to monitor D-Star.
Icom has a variety of D-Star transceivers that would obviously work fine to monitor. As far as receivers are concerned, the IC-R2500 has an optional D-Star board option.
BTW: Depending on which D-Star system you want to monitor don't forget to check out the audio streams on RR. There are a number of D-Star streams available to monitor.