Ah yes, I see what you mean about there not being an obvious spot for a menu button. But thank you for the reply and giving it some thought, I realize that I'm very late to the party since I only started playing the game about a month ago. It's not that important anyway, it's just one of those things that would be nice to have.
The one possibility I considered was having it top center, either permanently or having it sort of pop up/slide out when you move the cursor there, since that would look the least out of place I think. However that would require that you'd still be able to scroll the map at any point along the top edge of the screen, even moving the cursor "above" the button, otherwise that might get annoying. So yeah, I completely understand that it would probably be more trouble than it's worth trying to implement that.