[beagleboard] Should the beagleboard display at least something without a working SD card to boot?

Until code is loaded that can tell the processor what to put on the display, the display will be blank. If the original load that came with the board works, then my gut tells me what you are putting on the SD card is not working. If that is the case, there could be many things that are wrong.

I suggest you hook a terminal to the serial port and see the messages being printed out during the boot process.