I agree with Mattia. The flatsawn paduak could work just fine, and no doubt there will be some examples when people will tell you its worked fine for them. But laminations and carbon fibre are bloody good insurance to make sure it works fine and you have a stable neck.
Oh, I recently made a one peice flatsawn paduak neck (not neck through)with no CF and it worked fine for me Actually it hasnt, the action has become quite high over the past few weeks, just needs an adjustment of a truss rod in this case but i wouldn't have had to bother if i had laminated and used CF, and who knows how often i will have to play with the truss rod on this one, it seems like its going to be a regular mover to me.