I read so much about this being used at the high end and yet I cannot find it anywhere.
Filmtools have a 6' x 6' piece but the photo tells me nothing.
Any clues as to what it really is and where to buy?

I researched this some time ago. If I remember correctly, it is a trade name for a sandwched material that bounces well, and has nice handling.

The Rag Place - Hollywood's Premier Source for Motion Picture Technical Fabrics (http://www.theragplace.com/bounces.htm)

Thanks Perrone,
The Rag Place has a wealth of desireable goodies. My next challenge will be getting them to ship some half way around the world at a reasonable price.

Ultrabounce has a bit of a sheen to it and is an efficient bounce, i.e. maximum transmission. It's good when you need the most bang out of a bounce of a given size. For a more natural look we use bleached muslin, which is not as punchy but softer. As always, use the largest bounce you can manage as it will look the most natural.