Just a quick update here: Ivan (who gave the magnificent Virtual Firewalls talk at Troopers recently) blogged about this and some guy added some feedback from an environment with Cisco FEX and “one of the server guys start[ing] a Citrix Netscaler” ;-). See the second comment to his post.
This shows, once more, that the dependencies of various technologies (and what they are used for) must be well understood in cloud/virtualized environments. Complexity … but who do we tell. Y’ all know that, right?