If you go for the design that I have, you might not find it that hard to remove the top to switch cps.
I use black weather stripping instead of a bezel between my monitor and my top. The top on my cocktail is not attached to the cab any way but the weather stripping forms a pretty decent stick so the top really isn't going anywhere. Even before I had the weather stripping the top was pretty stable from going anywhere. If you are really worried about it, just put a piano hinge on the backside to hold it to the cab.
I think the best way to make removeable cps for a cocktail is like the example. I think doing it any other way will result in some sort of mounting bracket on the outside of the cab that would be visible when the panel is removed.