Cisco Switching/Routing :: 6500 - Randomly Devices Will Drop Offline And Then Come Back

I have a network that has a pair of 6500 switches on either end, running HSRP. In between each 6500 are two to three ruggedcom switches. They are connected to each other and the 6500's by trunk ports in a straight line. The 6500's see each other as CDP neighbors, and the 6500's can see the rugged- com as LLDP neighbors (ruggedcom only supports LLDP).
 
The issue is that randomly devices on the ruggedcoms will drop offline and then come back. The problem is that the devices that drop offline are all in the same VLAN, so it appears like a virus -  i.e. one device drops off, then multiple. Eventually the HSRP starts flapping between the two 6500s and this causes havoc on the network.I'm almost to the point of taking a laptop and plugging it into one of the ruggedcom's to see traffic, but the issue is that the ruggedcoms are outside in cabinets that laptops shouldnt be exposed to.