10000 people on Maps doesn't sound right. There are about 35k Googlers (excluding Motorola). 1/3rd on Maps? Implausible.
From Google Q1 2013 earnings report: "Headcount – On a worldwide basis, we employed 53,891 full-time employees (38,739 in Google and 9,982 in Motorola Mobile and 5,170 in Motorola Home) as of March 31, 2013"
http://investor.google.com/earnings/2013/Q1_google_earnings....