any howto-s on minimal jail installs with ro-nullfs-mounted /bin,/usr?

[Hari Bhaskaran]

Hi,

I need to create a minimal jail install with as much data shared
with the host as possible. So I believe I can read-only (null-fs)
mount /bin and /usr into paths that fall in the jail's fs-space.
I have tried /usr already (works fine - so long as I use /home
for home directories instead of /usr/home). Since the jails are
not meant for an ISP like setup, it would be acceptable for me
to have non-writeable /bin, /usr/bin, /usr/local etc. I can use
a nonstandard PREFIX for all custom packages I install inside
the jail. Are there any howto's on this kind of setup?

For example, most of the steps in "make installworld DESTDIR=?"
looks redundant since I would be clearing the /usr and mounting
from host later on. 

Any help is appreciated. BTW, I am on 4.8

Thanks
--
Hari Bhaskaran