Issues with 2011 Macs and netboot.

So, I've been having this issue with the post Lion 2011 macs (Mini and Air and with a firmware update, now the MacBook Pro) Damn things won't netboot. :( and I've been pouring over all the netboot documentation I can find to try and sus out why these new Macs won't netboot. Anyway, we are hosting netboot from a distributed network of ]linux DHCP servers (https://www.afp548.com/article.php?story=20061220102102611) and for the last 5 years or so this has worked perfectly fine (and still does for pre July 2001 machines). I did a packet trace on the new Macs and it appears that during the DHCP DISCOVER the macs no longer send the vendor class identifier. This causes the macs to be offered our standard linux PXE boot environment (that we use for the PC fleet) at which point the machine defaults to booting from the local disk. So far I'm at a loss as to what to do here. We are in the process of re-writing parts of the code so that we can specify "option root-path" on a per MAC address basis but I'm not confident it will solve the issue (not to mention we'll need to enter in these options every time we add a new machine rather than rely on a class). I have a thread on apple discussions here https://discussions.apple.com/thread/3433338?tstart=60 but no replies so far. I have also tried setting up a netboot server using Lion server. The client machines will see it and I can select it from the startup disk pref pane but still won't boot. From what I can tell it gets as far as DHCP SELECT (or something to that effect...don't have it in front of me at the moment) and then boots from local disk. Any thoughts on the issue would be greatly appreciated. :)