Getting a version of iPXE that supports vlans
Download
ipxe_with_vlan_support_2014-06-12.iso
Build it yourself
git clone git://git.ipxe.org/ipxe.git cd ipxe/src sed -i 's///#define VLAN_CMD/#define VLAN_CMD/' config/general.h make
There is multiple ways you can use your compiled binary, for testing just mounting bin/ipxe.iso and booting from it is good.
Using it
Boot from the ROM/ISO.
CTRL+B to get a command line when prompted.
Then assuming a desired vlan ID of 123:
vcreate --tag 123 net0 dhcp net0-123 chain tftp://${next-server}/${filename}