While Stack Overflow questions often contain segments of pseudocode or purposely abbreviated code in order to make the question more palatable to other readers, for something like a Code Review, the asker is generally going to have to post their actual code that composes a given system (otherwise the code review itself is kind of null).
I can see plenty of cases where this could easily lead to several hundred lines in a typical posting. Shorter reviews (i.e. 5-4 lines of code, and a question like "should I use X or Y to accomplish task Z?") should be posted on Stack Overflow instead, as such questions generally pertain to use of specific language features, or syntax attributable to a given language, not to the design of a system or it's code.
Is it appropriate therefore for code listings to be longer in a Code Review question? If so, how long before we would call a system unreasonable for a question and answer site?