I am also just wondering if I can say the following sentences?
1) ni3 zuo4 shen2me gongzuo = what work do you do?
2) ni3 zuo4 shen2me shang4ban4
1) is correct. 2) is wrong.
In 1, "work" clearly becomes a noun, which means "job", "career".
shang4ban1 cannot become such a noun. Actually, shang4ban1 itself has a [verb+object] structure. shang4 has the meaning of "go (somewhere)", and ban1 has the meaning of "job, work shift".
zuo4 shen2me shang4ban1 "do what go work shift" does not make any sense.
I suggest you to study the meanings of basic Chinese characters, instead of trying to substitute every word you think have similar functions.
If you've got the idea of shang4 and ban1, you'll understand that shang4 shen4me0 ban1 is possible.