No, come to think of it, but it'd be a much smaller market and substantially more complicated re power and pinout, especially if the host didn't have a regulated 5 & 12V supply...There are tons of adapters to fit a 3½" drive in a 5¼" bay, but has anyone ever seen a 5¼" to 8" adapter (either full or half-height)?
I was thinking about it this morning, and drew a blank.
I'm not familiar with the screw spacing of 8" drives. I haven't seen one either but yeah you would think that would have been something more often seen, especially with folks modding their Tandy's, etc.
Is an 8" drive really 8" for the mounting? Were they standard as far as screw spacings?