How can I determine the maximum supported resolution on a given Macbook?
While I don't normally like to post 'link only' answers, this needs to be an exception.  The answer to your question will largely be 'it depends on the MacBook'.  

To help you figure it out, I recommend going to EveryMac.com's MacBook Pro section.  This site will list the technical specs of every MacBook, including the maximum external resolution.

For example, here's a partial tech spec for a 2010 13" MBP: