NFS-homes: suggestions for resiliency

[urgrue]

I'm mounting /home via NFS and would like to make it as resilient to NFS
problems as possible.
The main issue of course is that NFS being down prevents you from
logging in because it hangs trying to read your .profile etc.
I can easily replicate the NFS-shared /home to a local directory, and
use that in case of an issue, but I haven't quite figured out a good way
to allow users to log in when /home is unresponsive.
I'd be happy with a shortish timeout that dumps you in / instead (same
as if /home didnt exist at all). I'd be a little less happy with a
kludgey script to lazy unmount /home and enable the local copy instead,
but that's the best I've come up with so far.
But what I definitely don't want is users unable to log in at all.

Any suggestions?