It isn't *necessarily* on the bottom level. Have played Wizardry for many years, actually the first time I encountered this dagger was on level *six*!The power of items that drop is directly connected to what kind of monsters you're fighting. Certain specific monsters have a small percent chance of dropping super-strong items, like this dagger. Basically you just need to wait it out and get lucky.
The other way to get a ninja is simply to have an Evil character and work him up to 17 of all stats, which allows for the Ninja class change. Takes a while, though...
Yeah, the chute is the only way to get to level 10. I'm currently playing the NES version again so if I find it I'll let you know how.One more thing, I'm posting my progress on gamefaqs.com in the NES Wizardry 1 board so if you want to make an account there and take a look around, go for it. I only visit here once in a great while... I'm on gamefaqs almost everyday.
No, I'm not trying to spam it or anything but it's a bit more active than here HOWEVER this site has a ton more info about the Wizardry games.