I've got the 19991204 snapshot booting on my Supermac C500.  It seems to
work great except that it didn't solve my problems with the de ethernet.
I tried using the tlp but with little success. I didn't see an entry for
it in any of the config files so I added:

tlp*    at pci? dev ? function ?        # Tulip based ethernet

and commented out the de driver.

The machine boots and seems to see the cards but not configure them:

Digital Equipment DECchip 21041 ("Tulip Plus") Ethernet (ethernet
network, revis
ion 0x21) at pci0 dev 13 function 0 not configured                      
       
Digital Equipment DECchip 21041 ("Tulip Plus") Ethernet (ethernet
network, revis
ion 0x21) at pci0 dev 14 function 0 not configured                      
       

ifconfig -a doesn't show any ethernet interfaces.

Any ideas?

cheers, 

Matthew Reilly