A couple of years ago I used to use sshfs quite extensively in FreeBSD and that worked fine. The only problem was the FUSE required root permissions to mount (unlike Linux). But aside that, it worked fine.
Hopefully they've since addressed the user mounting issue. I've not used it recently to check.
FreeBSD has had some work porting FUSE. I'm not sure the status I just remember seeing it as a GSoC project.
Some people are working on FUSE for OpenBSD. The GPL license of libfuse seems to be a problem but the kernel side stuff is implemented: http://comments.gmane.org/gmane.os.openbsd.tech/31704