Hello Eddie,
We do not make an outdoor sub and don't have any immediate plans to offer one. I don't have a lot of experience with outdoor subs myself, but I do know that the outdoor lines by Klipsch and Boston Acoustics are generally well regarded.
You wouldn't want to run a sub off of a center channel since that track largely consists of dialog. If you don't have a dedicated sub out, running it off the B channel, or if its a powered sub running it in parallel with your front speakers is a better choice.
Hope that helps!
Jason Hicks
Aperion Audio Guru