I used one of the articulated mounts that was rated for up to 60lbs.
I removed the overhead TV, then fitted a few pieces of 2X4 to support the new mount. I attached the 2X4s to the sides of the existing cabinet, then mounted a vertical piece of 2X4 to support the TV mount.
Because the mount is articulated, it's very easy to access the space behind the tv in the cabinet.
To secure the TV, I took 4 short pieces of black velcro and secured one piece to the inside edge of the frame, then placed the mating piece on the outside edge of the television. I did this in all 4 corners.
This allows me to push the tv back against the cabinet frame and secure it in place with the 1" wide velcro strips.
Only mistake I made was when I first put the velcro on, I accidently covered the remote sensor on the TV. Everything looked great, but the TV wouldn't turn on?...took a second to figure that out, moved the velcro, and everything was perfect.
I think I paid about $60 for the mount at BJs.
Jim