I upgraded the 15 inch in our '06 23H to a 19 inch . . . . which doesn't help you any. I measured the space a new one had to fit within (the maximum width in my case) and then went looking online for a modern TV which would fit the space . . . . and run on 12 volts - I found several. There are many small TV's which use an AC to DC power supply and will run on 12 volts, but aren't advertised saying they will, so more research was needed to sort those out. The one I bought made no mention of running on 12 volts and didn't come with a DC cable, but it works just fine
The original 15 inch had a square screen and the new 19 is a wide screen, so I did have to modify the mounting bracket a bit - The bracket hung down about 4 inches below the larger TV. Removing the steel bracket and cutting it off turned into a bigger project than I first imagined, but well worth it to have a high def TV with an HDMI port for a Blu-Ray player
You may get lucky and your swap might be more 'plug and play' than mine was, but even if it turns into a bigger project, you won't regret it when you're done
Don