I FOUND THEM!
I finally located the microwaveable trivets that I have been trying to find and they are on sale! If you are interested go to www.CSSDeals.com
and put "table top heat" into their search box.
(Reanie, I did check EBay and found two used ones. The descriptions -- table top heat, etc. -- eventually led me to the above website. Thanks for the hint!)
Again, thanks to everyone!! Merry Christmas!!!