> The sbus quad-ethernet is supported, I think.

Yes:

hme0 at sbus0 slot 1 offset 0x8c00000 level 4 (ipl 7): Sun Happy Meal Ethernet (SUNW,qfe)
hme0: Ethernet address 08:00:20:19:54:5e
qsphy0 at hme0 phy 1: QS6612 10/100 media interface, rev. 1
qsphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
hme1 at sbus0 slot 1 offset 0x8c10000 level 4 (ipl 7): Sun Happy Meal Ethernet (SUNW,qfe)
hme1: Ethernet address 08:00:20:19:54:5e
qsphy1 at hme1 phy 1: QS6612 10/100 media interface, rev. 1
qsphy1: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
hme2 at sbus0 slot 1 offset 0x8c20000 level 4 (ipl 7): Sun Happy Meal Ethernet (SUNW,qfe)
hme2: Ethernet address 08:00:20:19:54:5e
qsphy2 at hme2 phy 1: QS6612 10/100 media interface, rev. 1
qsphy2: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
hme3 at sbus0 slot 1 offset 0x8c30000 level 4 (ipl 7): Sun Happy Meal Ethernet (SUNW,qfe)
hme3: Ethernet address 08:00:20:19:54:5e
qsphy3 at hme3 phy 1: QS6612 10/100 media interface, rev. 1
qsphy3: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto

Martin