My wife was a building inspector in Texas and she says that you might have two options depending on the inspector.
1. Conduit all the way either in the bottom or the top. (the most code compliant)
May or may not pass depending on what the inspector will accept for the wire being protected.
2. Put a nipple on the conduit you have, drill a hole to fit the nipple in a 2x6 to run horizontally so i looks like the nipple is threaded into it, mount your panel to one side or the other, run the wires to the top and in with a clamp in the panel, then completely box the wire in with 2 x what-ever so that it is "protected".