Another version is this: http://www.mouser.com/Search/m_ProductDetail.aspx?R=SKQGADE010virtualkey68800000virtualkey688-SKQGAD http://www.mouser.com/Search/m_Pro

Another version is this: http://www.mouser.com/Search/m_ProductDetail.aspx?R=SKQGADE010virtualkey68800000virtualkey688-SKQGAD http://www.mouser.com/Search/m_ProductDetail.aspx?R=SKQGADE0... That one requires more force to press. It's also more expensive, but it's in stock now. It has the same footprint, so it'd be good for prototyping.