absolutely, i played a 3-6-1 formation when i was stoke, and was really succesful, won 3 titles and a champions league in 6 seasons, but it really depends on who you have in cb, you need really good CBs to make it really effective
Sounds like I'm just using this to boast, but that's exactly what I did in FM 2010 with Port Vale. Went 3-5-2 and walked league 2, Brandy was a machine for me.
Tried in FM 2011 with various teams with little success though.