mount --bind equivalent? mount_null broken or not?

I've been using mount_null for quite some time to mount filesystems 
beneath chroot jails, and have had no problems. However, the man page 
for mount_null has had a warning (since 1995, apparently) that "IT 
DOESN'T WORK", and I know OpenBSD has removed nullfs support as of 
version 3.7 (per 
http://archives.neohapsis.com/archives/openbsd/2005-09/0198.html). The 
bug listed in that thread doesn't appear to apply to FreeBSD, as I was 
able to successfully null mount /dev and list its contents. So my 
questions are:

1. is nullfs actively supported on FreeBSD? If so, are there plans to 
continue supporting it?
2. If not, is there another way of mounting filesystems to alternate 
directories on the system, as linux's "mount --bind" does? Or will mount 
--bind be added to the FreeBSD mount command?

Thanks

-Jim Keller