Good news. Looks like newer sound drivers are coming to Qemu in 0.14
(Maverick has 0.12.5, but Natty has 0.14) that work with Windows 7.
http://wiki.qemu.org/ChangeLog/0.14
Sound
* New Intel HD Audio support (commit), adding three new devices:
From reading the VirtualBox site they had the same problem, that none of
the emulated sound cards would work with 64bit Windows 7/2008 as they
are all too old chipsets. They solved it by adding a new sound card to
Virtual Box ('Intel HD Audio'). But appears this remains a compatibility
'bug' for
