Mass-produced in-wall? No. Custom in-wall? Yes.
Many quality receivers have two independent zones available - one is surround capable with a separate subwoofer channel, and the other zone is just plain stereo (which is likely fine on the porch or pool).
The main issue I ran into with that is the 2nd zone will not be able to play a digital signal. So if the OP is using an HTPC or HDMI from a DVD player, virtually no receiver can convert that digital signal to an analog signal.
I had to work around that for my house. We use the HTPC for music and streaming some TV. So we use the HDMI output for the video and have to make the computer use it's S/PDIF output for the audio. the signal goes into our indoor receiver for movies and music, then through the S/PDIF output to go to a S/PDIF input of a separate receiver that we use for our patio music.
Maybe I'm just stupid and did more steps that actually required, but once i figured it all out, we love the final set up.