I think that people who tend to have these 2 plants tend to hold on to them. They really aren't in the group of easily propagated plants (from, say, a stem cutting) and they are so pricey usually no one wants to chance it. I have not seen any for sale at a 'reasonable' price, ever. ESPECIALLY the Chainsaw hybrid.
I have a seedling of Wendy that is probably 2-3 years from being a nice plant. I got mine from a friend who got it from someone who was selling seeds and raising the seedlings. She was not sure she could have it survive so she gave it to me. Like most of the strap leaves its very very slow to grow from seed. But I have it, and I have the red scherzianum and an orange speckled Scherzianum hybrid and I plan to try at some point to raise my own crops of Chainsaws.
One place that I know regularly has Wendinglerii is Enid at NSE, but they are usually at auction so not inexpensive by any stretch of the imagination.
I am not sure if Ecuagenera USA ever has them, I have never seen them there.