I found a set of both the large and small on e-bay. I have both sizes and was curious about them being so hard to find. A while back I discovered that old or older discontinued sewing/quilting items can be found on ebay. Never had a problem with buying on ebay, although I do use paypal. The makers do make oval yo yo's very easy.
https://www.ebay.com/itm/Yo-Yo-Maker...kVnu:rk:5:pf:0