Mind you that the whole idea of kickstart is to be non-interactive
when
done correctly, and your idea blows that to smithereens. I think you
could better use DNS to select the best ks.cfg, see man dhcpd.conf,
although that would be less flexible.
...a couple of other suggestions:
Remember that the other end of the url you give kickstart doesn't need
to be a static file. It can be a cgi script that writes a custom ks.cfg
based on url arguments, dns, subnet, or whatever.
Also, I once had a student who wrote self-writing kickstart files. by
having the %pre script modify /tmp/ks.cfg based on, well, whatever.
That said, while I agree that the point of kickstart is to be
non-interactive, I don't think it would "blow that out of the water" to
have one non-default mode of operation that employs an interactive, but
very useful, menu system with less trouble than burning a custom
boot.iso every time you want to add an option.
--Brad