Someone on IRC was kind enough to provide me with an account on an OpenBSD machine so I could toy with porting some of my code. I decided to start with reading process information.
Things haven't worked out so well. Some admins unmount/proc (or never mount it in the first place) as a security precaution. I'm not sure what this protects the system from given that ps is still available, but then I'm not a hacker.
So, reading from/proc is out. The next plan was to use the kvm libs, which looked simple enough. Unfortunately, attempting to use kvm_open() fails with "/dev/mem: Permission denied". So, if an admin is security conscious enough to disable/proc, they're probably going to prevent the use of kvm as well.
What I don't know is whether or not this is a typical setup for OpenBSD. I can always resort to parsing 'ps' - NOT.