Update! I got ahold of Rapid Repair, the only place that fixes these things, and they don't have any parts for 2nd-gen Zunes available for purchase online so I emailed them. You know what the guy said?
The protective glass is not part of the LCD screen, you don't need to buy a new LCD. We don't currently have the glass in stock but it is not the same part, as the glass is actually connected to the front housing. Which is why I was going to attempt to remove the glass and replace it- it really didn't look like it was connected to the LCD, there's a few millimeters separating them. I don't know why three Microsoft phone people lied to me and said I'd need to acquire a whole new LCD, or why they wouldn't sell me one.
But this is one MS customer (who will only buy their OSes in the future) who's not going to get suckered into wasting more money on a part I don't even need!
-------------------------
ASRock M3A785GMH/128M
Phenom II X4 925c2 @ 2.80GHz (95W)
OCZ Platinum PC3-1333 2x2GB 7-7-7-21
WD5000AADS
Raidmax RX-500AF
Check it out.