The oldest project l2filter is almost certainly doomed. Patch no longer apply after ipfw3 was imported to -CURRENT and then merged to 8-STABLE. It still applies to 7-STABLE, but I don't use 7-STABLE. Merging only support for layer2 filtering with pfil and pf should be rather trivial. I'd like to keep patches in sync with recent -CURRENT but.. no time, no testers.
pefs looks much better. I keep using it myself, it looks pretty stable with my workload, although I've once got a pefs-related panic but wasn't able to get a dump. I'd like to implement lazy file extend (lazily write encrypted zero ranges to file after extend) and post it on freebsd-hackers@ once again.
This summer I'll work on namecache. Project is rather ambitious and innovative, in few words it's about generalizing UFS' dirhash and exposing it to upper layers so that it can be used for reliable full path lookup.