Some of what you're looking for here is available by clever use of the search operators that the Google maps interface (that's where we get our location info from) allows.
Check out this
blog post and this
forum thread for some options. Expanding OmniFocus' location awareness is one of the things we're working on; unsure of the status of the 'multiple locations for a context' idea. If you
email the support ninjas, they can add attach you to the existing request or add a new one as appropriate. (One of the metrics we use when planning our work is the number of customers requesting a given change...)
Hope this helps!