I'm currently investigating this same issue. I'm looking to alert on Nodes and Pools. I did an SNMP walk of an F5 and found this OID for Pools:
1.3.6.1.4.1.3375.2.2.5.3.2.1.11.20.84.101.114.109.105.110.97.108.95.83.101.114.118.101.114.95.80.111.111.108.1.4.(IP address)
which translates to:
ltmPoolMemberMonitorStatus.20.84.101.114.109.105.110.97.108.95.83.101.114.118.101.114.95.80.111.111.108.1.4.(IP address)
I'm going to create some universal device pollers for polling against the F5 pool members and create some custom alerts for the returned values.