DHCP times out during kickstart

I'm encountering the same issue reported here:
https://bugzilla.redhat.com/show_bug.cgi?id=189795

I've tried all of the recommended boot options that fix it, and port-fast is enabled on our switches. It seems to get an address about 3 seconds after the timeout, very consistently (if I look at the alt-f4 console).

It would be great if the options listed here (http://fedoraproject.org/wiki/Anaconda/Options) for fixing this problem worked.... specifically:
dhcptimeout=
nicdelay=
ksdevice=<mac>
linksleep=

dhcptimeout being the simplest solution, and ksdevice is required most of the time in multi-interface machines.

Happy to provide any further info to help.