Handheld terminal suggestions welcomed

Using Arduino Project Guidance
#1

I am planning my next project. To be a handheld terminal.
Here are some things that I am considering to incorporate:

  1. 64 key keypad
  2. 4X20 LCD display
  3. TTL/RS232 input perhaps 422/485
  4. Selectable baud rate (Dip switch or keyboard selectable?)
  5. Several front panel LED indicators
  6. Some analog input capability. Perhaps some digital I/Ps. Maybe a few digital O/Ps
  7. SD card data logging capability (using Bobuino2 board)
  8. Simple sound output capability (piezo)
  9. Internal/external power
  10. Perhaps wake up on external interrupt
  11. RTC

Do you have any suggestions?

#2

There are a number of different terminals it could emulate.

Has a list of some of them.

#3

What, no wireless?
Sounds good.

#4