I just configured LACP over a tunnel and used SPAN to capture the LACP packets entering the tunnel. See the config below.
The key is "l2protocol-tunnel point-to-point lacp" to allow lacp through.
interface FastEthernet0/21
> switchport access vlan...
I have used both Network Scrutinizer and PRTG. Both have free versions:http://www.plixer.com/products/netflow-sflow/scrutinizer-netflow-sflow.phphttp://www.paessler.com/prtg