Can an LTM be connected to a Cisco FEX (fabric extender)?

Mmm... Single arm implies single VLAN...

You don't have to have to have a single VLAN. You can trunk (cisco trunk, not F5 trunk) the port-channel and have 'internal' and 'external' vlans... At the end of the day, the BigIP doesn't care if external and internal vlans are on same or different physical interface.

I also use vPC's...So I have a single trunk at the BigIP connected to two 7010's in a vPC. So long as you're not doing routing protocols that works fine (Nexus can't do routing protocols on an SVI that's connected to a vPC)

H