The Journal seems to require magic storage HW for the current hash. Why not just write the whole log file there? It really isn't hard in 2011 to hook a microcontroller with an SD card slot and a USB port to the host. Add some software and you've got a cheap secure append-only store that can hold 16GB. You could put a reset switch on the package so that if you were to fill it up (hing: you won't) you could clear it and start over.
You get to keep your logs as textfiles, you can search the secure copy, almost no software has to change. Seems like The Journal done right to me.