I want to put a new TV in a 70”W x 40”D space located next to a fireplace. I don’t have cabinets filling this space to hold the TV (yet). Until I do get custom cabinets, I want to get a new TV for that space and am planning to make it work with a TV stand.

Upon searching what’s available, I can’t find TV stands or even free standing floor stands that offer a TV mount that will extend out (at all!) so that the TV can be positioned for others at the opposite end of the room to see. I've found some TV stands that have vertical posts that swivel, but not extend. Also, I know one can buy articulating mounts separately, but they all seem to be for wall mounts.

I realize the issue is risk of tipping. Still, I'm surprised there aren’t some stout TV stands or floor stands that can counterbalance a 45-70 TV that extends a bit.

I’m looking for something to work with a 50+ in. HDTV (still to be purchased.) Anyone have any experience getting a TV stand that has a mount that both extends and swivels?

monoprice.com

I think your only option would be to get one of the tv stands that has a wall panel built into it, then you'll have to install your own tilt/swivel/extend wall bracket (monoprice).

If you're looking for one on the cheap, ikea has several options for tv stands with an integrated "wall" panel.