No switch is needed, once Chameleon is done, what you see when booting verbose is being written to a file each time you boot.
This is not mentioned in the Chameleon docs because at that point the boot process has been handed over to the OS and you would look at the boot logs the same way you would look at them on a real Mac.
Look for kernel.log and system.log in /private/var/log.
On a working system you can run Console.app and browse all the system logs.
If you want to see what Chameleon is doing while it's preparing to boot OS X, add wait=y to /Extra/com.apple.Boot.plist.
On a working system, you can copy bdmesg (built when you compile Chameleon 2.0 RC5) to /usr/bin and then run it from terminal once OS X is running. This will provide the same output as wait=y.
As we discussed earlier, booting with -x does not mean that you are booting "without kexts". Booting with -x is the same thing as holding down the shift key when booting OS X on a real Mac. That is the reason why it's not documented here - Apple does a great job with that already:
http://support.apple.com/kb/ht1564