you would be better off asking around OP:X division dicussion and vent channels, a lot of us play it so im sure you could probably find someone to play with
If you have Arma and haven't played with the Op:X crew you're missing out.
Your best bet for everything you mentioned is to join the Arma rooms in the Op:X section of Ventrilo and to post anything and everything Arma related in the Arma section of the forums located HERE.
Our members regularly play Day Z. However, anyone who has Arma II and Arma: Operation Arrowhead can play Arma: Combined Ops. The Op:X guys play different game modes nightly including zombie variants and special forces missions. If you have Arma and all you're playing is Day Z you're missing out.