Thanks everyone for the clarification. I didn't realize there were so many
of the Calypso phones still available *new*. I was only aware of eBay and
some obscure Polish auction site. Now that I know they are available in
single quantities from AliExpress, that's a whole different scenario.
With those kinds of quantities, you are all correct that there is no need to
even think about a hardware design.
Thanks for all the feedback and keep up the great work!
Scott