Thinking about it.
I will nip down to a sheet metal shop tomorrow and price it out making some A5 ones with a thigh form on the bottom. And also some plain metal A4 IR knee boards.
Whats your wish list for it?
How thick do you want the strap?
Do you want elastic and velcro or webbing with a quick release?
How much grip do you want the clip to have?
What surface do you want? Dipped in plastic or plain metal?
A McFlurry is something that the peasants eat in McDonalds. It comes with a tapered plastic spoon which is hollow. It is the perfect size for a pen holde. I can't claim the invention rights for using them for this. They have been glued to various aircraft I have flown.