If when you press the the eject button there's no sound of a motor trying to eject the tray drawer it is unlikely to be a simple mechanical problem with the disc drive. Getting the drawer open isn't going to be of much purpose as the same motor also raises the laser carriage and clamps the disc.
There's no eject button apart from the one with the LEDs. There is a manual eject facility which involves poking something long, thin but stiff (like a ballpoint pen ink cartridge) down the hole adajcent to the disc drive drawer on the front of the Xbox.
It sometimes requires a fairly firm push and may help if the back of the Xbox is propped up so that the front is point down at an angle. You should feel resistance when you poke the tool down the hole but press against it and the tray drawer will be pushed out a little way, enough to pull it open.
I'd suspect shambles1980 is right about it either being a trace or front panel PCB problem of some sort but I was also wondering if you have you checked the cable connections to the disc drive are all press fully home?
Edit: I posted this before I read your news about it now working but still might be useful so I won't delete it.
This post has been edited by fallenangle: Jul 14 2012, 04:43 AM