I feel your pain.
I do have plans to refactor the openGLCD library which will make it easier to add support for alternate i/o interfaces like using an i/o expander like the MCP23017 or even using simple shift registers.
I plan on including support for each.
It's been on my list for quite some time.
I just haven't gotten around to it.
For now, about the only alternative is to use some other library or use an Arduino with more pins.
Perhaps a Teensy++ or a Mega.
Mega2560 boards are under $10 USD these days
and a Teensy2++ is $24USD.
openGLCD currently supports both of those platforms.
--- bill