double tagged vlans on 6.0

[Donatas]

Just wonder - what is the major reason double vlan support (also known as q-in-q or nested vlan)  is still not included in freebsd. The need for this feature is growing parallely with new L3 switches being available (cisco, allied telesyn, foundry networks etc...). Enabling this in some cases could make freebsd the only solution for backbone operators. 
Brook Davis mentioned q-in-q would make inefficient vlan code even worse...but that was some time ago...hope the situation changed nowdays