Some general thoughts about OpenRPN:
I like the concept, however, ...
My thoughts are that an initial step would be to develop an ironclad design specification with a high level of minimal requirements that would receive an "endorsement" as "OpenRPN compliant". Then bid out the design. Let the people with the best resources build it to the desired specifications.
Provide the specs to known calculator companies, computer companies, etc. A small startup electronics company may want to build the products. For that matter, put the specifications on a website along with FAQs, etc. If companies want to add bells and whistles, e.g., algebraic capability, no problem. That doesn't preclude individuals on this board from forming their own company to produce a compliant calculator.
The other advantage is that we could provide different level of specifications for distinct calculator forms. I would like to see three separate specs for 3 different purposes:
1. All encompassing: Graphing calc, etc., with a more HP-41 style programming language. Would like to see some provision for argument passing mechanisms and local variables for procedures and more structured constructs.
2. Two liner: Compact calculator, perhaps the size of a 33S or 32SII but with power of 42S and external interfaces and flash memory.
3. One or Two Line Calculator for examination purposes. This would have battery backed solar power, multiple non-volatile memory registers, have unit conversions and scientific constants built in. Essentially equivalent to a 33S with no programmability and no non-volatile equation storage. This calculator should be really cheap. It would compete with the HP-30S, TI-3X, CASIO fx-XXX models.
All would have an ENTER key in the appropriate place and the appropriate size. All would have full RPN with RollUp, RollDown, LastX, X<>Y, and at least a four register non-volatile stack. All would have the NULL feature that would show the function and cancel the function if held for an extended period of time. All would have a 3 digit exponents and a degree of accuracy comparable to the latest models of HP calculators.
Also, provide an update cycle so that the specification can be appropriately amended from time to time as appropriate.
Issues:
1. Mechanism for creating and updating the document
2. Parties involved in creating and updating the document
3. Mechanism for tracking the progress of the document and companies interested in creating associated products.
4. Marketing: Convincing companies that this is a worthwhile endeavor and a money making proposition.
... As I said, just my thoughts