Jacques,
I had these made locally, about a year ago.
One of the chaps that volunteers at the Gympie Woodworks Museum made them for me. He got the sloping floor almost perfect. Quite remarkable, considering he did all the inside work with a chisel!
My only criticism would be that they were
too good. So good that I couldn't bare to paint them, out of respect for the craftsman.
If my memory serves me correctly, I thought it was Phil W. that sent me the plans. If not, my apologies to the actual supplier. The pair that were made for me cost $50.