I have to relocate a pfSense install to different hardware. The recommended way of doing this seems to be the config backup/restore routine, but as far as I can see this is missing stuff like Squid logs, Sarg reports, etc. . I'd like to have these on the new machine, if that's possible at all.

Could this be done by restoring a full backup created with the /etc/rc.create_full_backup script? The tgz archive created by that script seems to include the full file system. If I install the same pfSense version the backup was made with on the new machine and restore the backup with /etc/rc.restore_full_backup, will I get a working "clone" of the old system? Has any of you guys migrated pfSense to new hardware like that?

Will you also be replacing the harddisk?  Bad is not like Windows to scream when harddisk is attached to different system..

Or clone disk and plug in other machine reconfigure interfaces and test before migrating..