I was looking for exactly the same sort of thing, and i suddenly thought that what I needed was similar to what I use to raise my computer monitor, and slide my laptop docking station underneath.
SO, search google for a "monitor riser" usually used for raising a laptop or computer monitor, I have just ordered "3M MS90B Extra Wide Adjustable Monitor La..." from Amazon here in UK.
I had exactly the problem you guys had, and looking at the reviews from customers this item will be perfect.
This model goes to a reasonable height (15 cm) and will hold up to 40kg. Not all are so suitable for a TV.
This may not be the model you want, but at least the product is the sort of thing and you know what search terms to use.
I am new to this forum, so I cannot post any URL.