According to #12 in the B-2 Cohabiting Partners policy :
http://travel.state.gov/visa/laws/telegrams/telegrams_1414.html
"If such individuals plan to stay in the U.S. for more than six months, they should be advised to ask BCIS for a one-year stay at the time they apply for admission. If needed, they may thereafter apply for extensions of stay, in increments of up to six months, for the duration of the principal alien''s nonimmigrant status in the U.S."
Anybody tried this before? Thanks!