Many years ago while dealing with a FreeBSD (5.3?) box that randomly panic'ed and reboot (bad memory as it turned out), I came across a command in some forum post that when used would output information about previous reboots including the panic message. It allowed me to look back and see how often the issue was happening. I should have made note of it, I guess I relied too much on history to remember it.
It was an obscure (at least to me) command with a few args. It wasn't something I had to install via ports. I assume it relied on logs or dumps to collect the information. I think the output was formatted in two 40 character columns with most of the information in the first column. I think the panic message was part of the second column.
Does this sound familiar to anyone?