After you've finished building a prototype with mbed and have progressed to spinning your own custom product PCB using the LPC1768, the same program binary can just work on it too; the .bin files really are just a raw ARM binary images for the LPC1768 chip.
But you'll need a way to get it in to the microcontrollers FLASH. It looks like <<user daugihao="">> has been busy and written some code that turns your mbed in to a drag-n-drop programmer to drive the LPC1768 chip's bootloader, so you can use an mbed to program your custom board!
You can see his full write-up in the cookbook:
Looks like it could be very useful!