Does Mac OS X SNMP report cached memory?
Not exactly. It only provides via SNMP Memory Buffers, Real Memory, and Swap Space (hrStorageOther, hrStorageRam, and hrStorageVirtualMemory respectively) - you may find this cacti forum post helpful in making a script to grab that information however.
However if you're getting at time out instead of:
memCached.0 = No Such Object available on this agent at this OID
you may want to check your SNMP settings on the Mac (/usr/share/snmp/snmpd.conf or use snmpconf)