The IPX packet for echo does contain a TTL value analog, so packetstorm should be prevented, as long as the responding program does not modify the TTL and timestamp fields in a stupid manner.
There is no broadcast address with IPX either, so traditional packetstorm attack (Ping on the global broadcast, everyone responds, with compounding responses to responses, because of dumb TTL handling) should not even be possible-- All echos are unicast; The most you might be able to do is get an echo to bounce a few times between two hosts using a man in the middle to start the pingpong match-- the TTL will quickly expire though, and the bounce would stop.
Again, I tried to look for details about the actual data inside an IPX echo packet in the data portion, but could not find info. It's possible that additional Q0S measures use data in the data portion of the packet for sanity checking.