In other words, you ask, if it is possible to boot Windows from an external SSD? If so, sadly no. Maybe there is a workaround though.
As for booting Mac OS X (be it Mac OS X 10.5 Leopard, Mac OS X 10.6 Snow Leopard, Mac OS X 10.7 Lion or OS X 10.8 Mountain Lion from an external SSD or HDD, then yes, that is possible.
True, but I was thinking I could then put bootcamp on it & just have that disk with windows on and not my internal SSD in my iMac. Won't make much of a difference, but something to play with.
Yes, it is possible to boot Windows on an external SSD with a thunderbolt interface, and possibly with a USB-3.0 interface. It is reported that Windows will detect a slower FireWire or USB-2.0 connection and refuse to run as it is deemed to be "too slow".
There are several threads here showing how and discussing this topic already.
I am running Windows 8 on a Seagate GoFlex interface to a SSD via thunderbolt on a new iMac.
I'm using the GoFlex connector firewire, but not the Thunderbolt, I'll have to check that out. It's a fair amount more expensive, but I think it would utilize the external drive I have better. I have the previous generation iMac, so I wonder if that will cause problems? I know Googles my friend here.