Create Search for Google Maps in Opera
So I found the url to use to make Google Maps work as an search engine in Opera:
http://maps.google.com/maps?hl=en&um=1&ie=UTF-8&q=%s&fb=1&gl=us&ct=image&resnum=2
Just right click on the Google Maps search URL and then select "Create Search" but then expand the Details and set the above URL as the address. I also set "m" as the keyword so I just have to type "m New York" in the address bar. Hopefully this will be useful to someone else as well.