Yes, there was a OS 8 (8.0)... There were also system 8.1, 8.5, 8.6, 9, 9.1 and 9.2 with minor updates to some of them (8.5.1, 9.0.x, 9.1.x, 9.2.x). Not to mention OS X and it's updates and such. There was also OS 7.5 and 7.6. along with older operating system numbers.
System 1.1/2.0, Finder 1.1
System 3.0, Finder 4.1
System 3.2, Finder 5.3
System 3.3, Finder 5.4
System 4.0/4.1, Finder 5.5
System 4.2/4.3, Finder 6.0
System 6.0/6.0.3, Finder 6.1
System 6.0.5, Finder 6.1.5
System 6.0.8, Finder 6.1.8
And maybe a few in between.
P.S. aafuss1, for the record: In around System 7, they started using MacOS 7.5, 7.6, etc., at the same time Apple introduced the "smiley face" Finder/System/MacOS logo. From then on it's been commonly referred to as MacOS 8, MacOS 9, MacOS X, etc., not System 8. Usually you wouldn't use "System" unless referring to an early version of 7 or earlier.
Actually, there were two: Copland (the original), which was never released, and Mac OS 8, which we all know and...okay, it was okay.
Copland was actually quite advanced, although just right for 1996. Pre-emptive multi-tasking was there so it was fast and smooth. It also broke pretty much all the application software out there and didn't make it past the developer previews.
Just a slight correction! Copland, didnt have true pre-emtpive multi tasking at application level. It could only pre-emt. multitask in server mode. Next revision "Gershwin" supposed to have a true pre emptive multitasking. Same as Copland it never made it. I dont think that it even made it into developer hands.