Yes. You can use expect with /install easily and you can simply add your own local "site set" tgz which can be hosted on a local HTTP/FTP server to apply any local customisations.
However, if you're provisioning lots of machines, it's very easy just to "restore" filesystems off a bootable USB stick, mount them, set the hostname then tell ansible/puppet to do the rest. Don't need kickstart or any of that crap.
Personally though I'd just netboot lots of systems off PXE/TFTP, NFS mount all filesystems and have local swap disk only. I used to do that with Sun systems. We had 50 SPARCstation 5's booting off a SPARCserver 1000E on Solaris and it worked nicely. OpenBSD works pretty much the same. Linux is a piece of crap to netboot.
Plenty of ways to skin that cat.
You can netboot Linux. Knoppix [1] offers Terminal Server which configures DHCP, TFTP and NFS so that you can boot Knoppix from the local network.
There is an official solution in -current that involves DHCP but I don't know the details.
Let's see...
> Network boot, using PXE (i386 or amd64) or diskless(8) (other platforms).
Red Hat and Fedora had this for ages. Also the installa media can be on a FTP, HTTP or NFS server.
> External USB CD-ROM or USB floppy, if your machine can boot from one.
This should work with most Linux distributions, too.
> USB Flash disk or hard disk
The same.
> Worst case, if none of the above is suitable, you can usually pull the disk out of the target system, use suitable adapters to install it in a "normal" computer, install OpenBSD, then replace the disk back in the target system.
Again this should be possible with most Linux distributions.
Now does OpenBSD have an automated installer?