I found this, but I would be cautious about any case claiming to be for the Pro1 or Pro1x that doesn't show complete pictures. The case may fit, but does it allow the keyboard to open properly? Luckily Amazon allows returns...
https://www.amazon.com/Compatible-Qx1050-backplane-Silicone-KA-HEI16/dp/B0B8S3TXGM
My skepticism comes from seeing manufacturers in China relabel a case as for the Por1 or Pro1x just because it fits in one way or is a universal case they think might work, but these cases tend not to be actually created for the Pro1x.