@timofonic: Thanks for your contribution containing a lot of points and links which will take quite some time for checking and reading. Just allow me writing a few quick general remarks (based on my personal, mainly industrial experience) in arbitrary order:
- One of the best and most certain ways to kill a project is feature overload.
- If you want to be successful, make small steps and change one thing at a time.
Thus, what we will be trying with the "35S" as defined in the OP:
- We'd like to use an existing hardware platform as is but, alas, there's none suiting our requirements AFAWK.
- We will use an existing hardware platform as far as possible. Hence, we are not keen modifying anything unless inevitable.
- We will use as much of the opportunities the platform offers.
- We're not up to build a frankencalc. Hence, no manual "minor" modifications of existing mechanics. Either it fits or it doesn't.
- We will use as much of the existing firmware as possible. Hence, no RPL.
- We will make the UI as comfortable as possible for as many people as possible under these boundary conditions. Some complain about deep menus, others complain about their favorite functions excluded - we've to find a compromise.
Anybody wanting something significantly different, feel free to
convince us (or start your own project).
d:-)