A possible solution is to use the ethdevice=... bootoption which is available 
since grml 2009.10. Closing this issue therefor.

regards,
-mika-

Having a PC containing 2 network cards eth0 and eth1.

case 1:
eth0 connected to to a PXE-server with grml-medium, dhcp, nfs, and all the 
stuff, eth1 not connected

System gets ip-address via dhcp and boots grml, everything up and fine.
                                                                                                                                                                                
case 2:
eth0 not connected
eth1 connected to to a PXE-server with grml-medium, dhcp, nfs, and all the 
stuff, System gets ip-address via dhcp and boots grml but stucks at eth0, 
trying to mount the NFS-enabled share from PXE-server. No timeout, no try to 
use eth1

[bugreport by Pelle Esset, thx]