I wanted to share that CloudConcepts' method worked for us using a stock ESXi 5.1 ISO and the same E1000E.tgz driver. We purchased a few HP 8300 workstations that had the same NIC; these machines are also not on the HCL but it was a fair bet that HP was using the same NIC and driver as on the Z210. I tried just using ESXi-Customizer to patch in the .tgz without converting to a VIB and it worked flawlessly for us first time out (so yes, I'm `deprecated' but it works).
I could see using this method to make a Super ESXi with all of the HP and Dell drivers that are commonly not included in VMware's image and using it across our entire lab. Thanks Cloud for the wonderful tool! :-@)