Ports tree infrastructure

[Dan Casey]

    I am having trouble finding documentation that goes in more detail
then that of the handbook.  I am sending this message in hopes that you
may be able to point me in the right direction, or know of a better way
to accomplish this.

I am setting up a single server as a 'build box' for our freebsd
servers.  We want to build our own packages because
1. we may need to compile certain ports with different flags then
freebsd chooses.
2. We want to update ports only when needed.  Ie: Unless we need
something in a new version of a port, or unless there is a security
hole, we want to keep the old version.

What I'm setting up is a regular ports tree (/usr/ports) which is Not
updated.  Then a second tree /usr/local/current-ports which is updated
daily with portsnap.

When I want to upgrade a port, I would copy it over from the current
ports tree.  I'm not sure what to do about the INDEX files, which is
what i had trouble finding documentation on.

This looks like it is going to be a pain to maintain this.  Are there
any ports or scripts that pointy hat uses that could be helpful in my
type of environment.   Are there any better solutions?