a couple of ways of doing that:
A - fairly hacky, but keeps your home in /Users, and on another partition. add a startupitem that unmounts the partition from its default spot, and remounts it at /Users/catscout.
First, to get the device name, run df.
In my case, there is a line like this:
/dev/disk1s5 10020816 7491980 2528836 75% /Volumes/Faustus
So I could make a startupitem with a script that looked like:
umount /Volumes/Faustus
mount -w -t hfs /dev/disk1s5 /Users/catscout
B - not so hacky, but your home dir doesn't hang out in /Users all pretty-like. Just change the home setting for your account in netinfo
sudo niutil -destroyprop . /users/catscout home
sudo niutil -createprop . /users/catscout home /Volumes/whatever