I've tested this in Red Hat Linux 6.2, but I don't see any reason why this would be 
different on RH7.0, so...

In kickstart configuration, if you define networking with 'network' + options, it 
will be set up.  If that information is omitted, network won't be configured at all.

Would it be possible to code an option like:

network --prompt

which would ask interactively for the networking to be set up.  It could be either:

1) Done first so that networked install would use these and kickstart with bootnet 
without ks.cfg modifications or DHCP would be possible, or

2) Done later; this would only help for HDD/CD installs.

Note: I've noticed that running netconfig after the install will usually cause 
different network configuration -- and with kickstarts, running it might not always be
possible.