The 30GB downtime is no fun at all; drive spinning, battery draining, it's a drag honestly.
If you're handy with a small screwdriver (Philips or standard), you can pop the thing open and fix this problem quite fast. Keep in mind this CAN wreck your Zune if you're not careful or don't know what you're doing. This DIY solution isn't for everyone.
With a small screwdriver, lightly apply pressure on each end of the black clip and pop off the cover to the Zune. Underneath there should now be 2 Philips head screws. If the tool is small enough, turn these screws and remove them so that you can remove the case. Carefully (perhaps with your fingernail) pry the case up -- it should lift easily.
Now you'll see the back of the Zune. The black rectangle is the battery. Follow the lead on this over the back of the LCD to the plug. To make it easier on yourself, you might want to lift up the battery, then slightly pull on the ribbon cable to get it out. After you do this, let it rest for a moment before plugging the battery back in. This is where a steady hand comes in, since the cable can resist and might break with too much force. Slide the cable back in until it's secure (there should be a little bit of white showing still). The Zune should be able to power up once again, displaying the menu screen. Reattach the back of your Zune, returning the screws to their proper locations.
If all goes accordingly, everything should be fully operational.