Joe -
Linux can do this, check out:
More specifically:
http://www.lartc.org/howto/lartc.rpdb.multiple-links.html and
http://www.ssi.bg/~ja/#routes
I am working on a redhat project that requires QoS over multiple VLAN's.
I was reading up on tc and imq devices when I came across this
information. Haven't tried this config, but it look like it should do
what you want.
McLean