I've just updated jkstat.
The notable new feature in this version is the jfsstat utility:
This uses the new kstats introduced in Nevada recently - the kstats used by fsstat. So you need to be running Nevada build 35 or newer to see these. (ON downloads - you want SXCR build 35 or later.)
The other change that's part of this is that I've started to use JTable to display things. I don't know why I've avoided this in the past - I guess that JTable seemed rather complex, but once I had got the hang of it it turns out to be very easy. I'm also using TableSorter from the Java Swing tutorial, which gives me the ability to sort the columns for free.