I am working on a general proto board with GSM(sim900BE), RTC, (RS485 1/2 OR full duplex) with a switchover to USB
plus a pulse int input.
All component power are switchable.
The unused ports are fet into a header allowing a piggy back with display or whatever pops in mind.
The size is 99 x 54.5 mm.
I am due to produce the PCB. a small alteration, your input, could make this a perfect card for general usage.
This card will be used to control a rs485 network, temperature controller , measurement system, display control (numeric) and GSM/FTP/SMS status and alarm system.( so the poor pic18F8722 will be bussy) the quiescent current in sleep mode should be less then 800 micro Amp.
Is there any interest in this project?
Picbuster.