I've recently hacked up the Realtek driver (rtls) to support GLDv3. Its part of usr/closed right now (though I hope we can open source it!), so I can only share binaries.
Anyway, if you're stuck with this driver on your x86 system (because its on your motherboard, usually), and you want to try running a GLDv3 version of the driver, let me know.
The GLDv3 brings link aggregation support, VLAN support, and virtualization (IP instances) with it.
Of course the hardware is still somewhat crummy, so I wouldn't expect to get much performance out of it. But again, if you're stuck with it (as many people probably are) this may be helpful.