Yeah, I know what you mean, the Invisionboard OA has an option for low-fi at the bottom of every thread... The funny thing is that I've come across low-fi versions of GA topics when searching through Google, but can't find out how to turn that option on when browsing directly.
EDIT: HERE'S ONE WAY, replace "show" with "print" in the url above. But I don't know how to keep it enabled.