The hardest answer to find is the one directly under your nose.

Or at least have an optional relay board for low power GPO outputs?

It shouldn't be too hard to interface it with X10 and have it control just about anything in your house! That would be fun, have the lights blink in the whole house when ever you get email :'D

If you are just looking to get the system loading and not the actual kernel load you should be able to have init load a program that would follow the log file and output it to the display. This would show you things as they loaded as well as if they failed or not.

I think the display's are designed for more comercial aplications. The power connector also contains the I2C connection which can be used in place of the serial connection. Also I2C allows for multiple LCD's. At least according to the manual