I just found out: the vmxnet3 driver _does_ support jumbo frames, vlan tagging etc... however due to the
somewhat odd naming "vmx3f0" etc the pfsense interface name parser fails (it tries to seperate the driver
from the unit on the first number, which fails here). When these regex are fixed, the interfaces can be
used as vlan parents, and from what I could test quickly, they do work this way.
Here's an ifconfig of such a vmnet3 interface:
vmx3f0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=403bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,VLAN_HWTSO>
ether 00:50:56:8d:06:39
inet 192.168.166.1 netmask 0xffffff00 broadcast 192.168.166.255
inet6 fe80::250:56ff:fe8d:639%vmx3f0 prefixlen 64 scopeid 0x1
nd6 options=3<PERFORMNUD,ACCEPT_RTADV>
media: Ethernet 10Gbase-T
status: active
Here's one as a VLAN sub-interface (just used with tcpdump so far):
vmx3f2_vlan1101: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=303<RXCSUM,TXCSUM,TSO4,TSO6>
ether 00:50:56:8d:06:3b
inet6 fe80::250:56ff:fe8d:639%vmx3f2_vlan1101 prefixlen 64 scopeid 0xa
nd6 options=3<PERFORMNUD,ACCEPT_RTADV>
media: Ethernet 10Gbase-T
status: active
vlan: 1101 parent interface: vmx3f2
And this is all on ESXi4 with ESXi5-vmware-tools installed. Looking good so far

Cheers,
Markus