Reverse camera double din head deck stereo

Looking to install a double din head deck with reverse camera in our Toyota Landcruiser. Sounds like a simple ask. Problem is that due to having a canopy on the back we need to be able to run the video feed from the camera all the time while driving plus listen to the sound system at the same time. Alpine & Pioneer can do this in their high end systems but way out of our price range. In our previous truck we simply installed a separate screen for the camera but the cruiser has space to fit the extra screen without getting in he way. Local Retailers have given us conflicting "opinions" about whether lower end cheaper models can do what we need. Don't want to buy a unit & install only to find it can't do what we want. Can anyone suggest a head deck that will definately do what we want. Ive given up 'trusting' the advice of retailers. Price range – up to $500