Character LCD Serial Backpack pre-Project

I'm looking for comments and suggestions to make this more generally useful.

I have a pile of surplus character line LCDs based on the Hitachi HD44780 chipset.  There are oodles of these available surplus, and really cheap, like $2 cheap. The probelm I see for most modern MCUs is that the LCDs are

• usually 5V I/O (at least for the surplus parts)
• parallel and chew up a lot of I/O
• slow so they require a bit of code to poll the display or timed delays to insure reliable operation.

I'm not too motivated to reinvent the wheel, but all the options I've found seem to miss a lot.  I've seen the Adafruit board, but it's hard-coded at 5V (deal killer) and the 16X1 connector (inconvenient for displays with the 8X2 connector.)

I started thinking about a launchpad boosterpack that would provide a 3.3V SPI serial interface, but realized that it was too specialized and really didn't meet my needs. What I'm noodling about now is a 'backpack' board that is fairly universal.  It would match the standard 16X2 character board mechanical footprint and provide the 16X1 header interface connector AND the 8X2 connector that is the other dominant standard usually used on 2X24 character dispalys. It would also provide:

• A simple, sequential version of the HD44780 command structure - send the bytes, the board worries about handshaking and timing.
• SPI
• I²C
• Serial UART (Logic or RS232 Levels)
• logic levels from 1.8V to 5V - selectable
• backlight current control (settable by component value selection)
• dimming by MCU command
• contrast by MCU command
• on board regulator for board
• on board regulator forLCD including backlight
• most options selected by hardware jumpers
• ASYNC serial autobaud

I can fit all this on the board without a problem, but too many features results in too much cost and kills the advantage.  A lot of this is optional BoM stuff - as in 'don't need RS-232 - don't stuff this.'

I don't see any reason to:

• have more than one interface operational at a time - SPI or I²C or UART
• use variable resistors.
• use through hole components for other than connectors (would it be better to have backlight current setting as leaded resistors?)
• Use anything other than a 2X? 0.1" header for the external interface so:
  • no DB9 for serial
  • power on interface connector pins, not a seperate connector
  • no screw terminals

So, what do you think?