Hi Ian
I have one for you.
It is 1.2 by 2.4 when open.
I just had the mattrass re-covered with a strong canvas material.
I have a love / hate relationship with my RTT.
It is heavy, and I tend to recruit the two strong Malawians living in a shack nearby to help me put it on the roof rack whenever I need it. I pay them 50 bucks a shot!
I am of late, however more inclined to use the pop-ups with mattresses. Only real disadvantage is Lions, but as long as not all of my family is on the roof, this does not quite meet that criteria anyhow.
If you are itnerested, pm me.
See a picture or two here of it on my roof:
http://www.patrol4x4.co.za/viewtopic.php?f=57&t=4529