Well, I don't know about Asterisk Now, actually I don't know about any of those Asterisks 'ready to go'. However I believe that trixbox (
http://www.trixbox.org/
) supports Openvox cards by default.
You can install A1200P with AsteriskNow, but you need compile and patch the DAHDI/Zaptel. I remember there have some posts in this forum about procedure of patch, try search asterisknow in this forum