try -3.074570, -50.449243! i was literally shocked when those coordinates worked for me, as i'd been searching for over 24 hours (off and on). if you haven't found your mew yet, i honestly hope it's there too.
apparently they're sending prizes to everyone who caught all 151... but there might be a catch that excludes people who didn't post on some stupid google+ thread for google maps. FML.