I think if I were going to remodel the TV area and upgrade to a flat screen TV I would start by looking at pictures of the various RV manufacturer's websites and study how they have installed TV's in their trailers. Find one that you like and that has a cabinet/entertainment center similar to what your existing cabinet is like. Then start figuring how to make it look like the picture.
I agree with you, you really don't want to take a old tube type TV out of a drawer and sit a thin model flat screen in its place. It's not going to look right and you will lose a lot of potential storage space that way.
Go online, look at what's available in new models and see what really fits your style and your trailer, then "just git 'er done"
