What a great thread, took me hours to read the whole thing, then I jumped in my car and drove to the local HD (Biddeford, Maine) to grab some... They had some play sand but it was silica. Asked some nice lady about it and she said that Old Castle stopped shipping them the Tropical Play Sand about 4 months ago.
She called Old Castle to see if there was any available and she was told that their supplier went out of business and they could no longer get it! Then she used a computer to check all the stores in Maine, NH, and Mass., all came up with 0 bags of it.
On my way home I stopped in a LFS to see what their prices were, $36.99 for a 20lb bag!! Guess it's time to rethink the DSB...