I compiled a -current kernel, and lots more stuff got configured compared with 2.0.2.
But there are still a few holdouts:

Nvidia nForce4 Memory Controller (miscellaneous memory, revision 0xa3) at pci0 dev 0 function 0 not configured
Nvidia nForce4 SMBus (SMBus serial bus, revision 0xa2) at pci0 dev 1 function 1 not configured
Nvidia product 0x0057 (miscellaneous bridge, revision 0xa3) at pci0 dev 10 function 0 not configured

A quick grep through the sources indicates that there is at least an attempt at
supporting the SMBus in the nforce4 (this board has the nforce4 ultra, if it matters).

Any suggestions?