cRTP on WAN routers

Is anybody aware of a vendor that can supply a layer three device with the capability to pass 2000 or more simultaneous cRTP flows over ATM DS3 without running out of CPU? Each flow is 12Kbit/sec (with RTP header compression). Specifically I am talking about G729a traffic with a 30ms payload. Cisco's 7200 VXR NPE400 seems to be falling far short of our requirements and the larger chassis such as the 6500 doesn't support cRTP over ATM. I haven't tried the 7200 NSE-1 yet for this application because we have had tons of issues with those in an earlier unrelated deployment. Feel free to respond offline if necessary. Heath